I like you rewrite:

This essay will challenge the view that multinational companies do more harm than good by focusing on their contribution to economic development and improved living standards.

It is much better than mine. I always can learn some better expressions and find something that is missing in my writting through reading your rewrites.

Thanks Alison, too, for your comments. I agree with Alison on the need for a clearer thesis sentence,  and with her grammar suggestions in your intro.

Word Choice/Word Form/Usage

One of the main characteristic of the current century is widespread existence → One of the main characteristics of the current century is the widespread existence

various economical sectors → various economic sectors

there are many evidences → there is a lot of evidence

Ideas and support

In the introduction, you wrote:

Many think that multinational companies and their product will hurt the society eventually.

How? You could give some examples:

Many think that multinational companies and their products hurt society through pollution, increased materialism and corporate greed.

As Alison says, try to avoid generic (standard) sentences which could be used in a million essays:

This essay will challenges the topic by examinging both cons and pros of this phenomenon.

Instead, rewrite this thesis sentence to help the reader guess what is coming in your essay. Alison suggested:

This essay will challenge the view that multinational companies do more harm than good by listing some strong and positive evidence.

Or you could use something more specific like this:

This essay will challenge the view that multinational companies do more harm than good by focusing on their contribution to economic development and improved living standards.

Topic Sentence

Topic sentences should be short. In Paragraph Two you wrote this 27-word monster:

One of the fundamental requirements of establishing a multinational activity is the acceptance of the fact that the society shall prepare itself for welcomming many foreign individuals.

It’s too long and there are far too many nouns and nominalizations. Nouns or nominalizations slow down your sentences. Try to have fewer nouns in your sentences, or to replace them with adjectives or verbs.   Or just simplify and shorten:

To be truly multinational, societies should welcome foreigners. (8 words)  OR   Societies should be open to foreigners. (6 words)  

Paragraph Two is off topic. It's not clear to the reader that you understand what multinational companies are. Why not start with a definition? The essay does not ask what the conditions are for multinational companies.

Shorten/Simplify: Reorganize

In Paragraph Two you have only 4 sentences -  you should have about 7 or 8. They have an average sentence length of 31 words. This is far too long.  

I recommend having an average sentence length of between 12 and 15 words per sentence. Longer sentences tend to have more mistakes in punctuation, agreement and structure, as well as being more complicated for the reader.  Aim for a mix of sentences - long and short, simple, complex and compound. All four sentences in this paragraph have a very similar and complicated structure.

1. One of the fundamental requirements of establishing a multinational activity is the acceptance of the fact that the society shall prepare itself for welcomming many foreign individuals.
2. People who are opposed to this trend believe that the host nation usually could not impose its own culture to the foreigners and therefore the host nation could gradually accept many unwilling changes.
3. Dissidents also claim that the main purpose of multination’s investors is to find a target market in the host nation and thus be able to sell as much of their products as possible.
4. Extremist oppositions even argue that this type of establishments are only search for solutions to outsource more of their products so they won’t help in any way for domestic employment either.

Off-Topic?

Another problem with this second paragraph (a HUGE problem) is that it is off-topic, at least in the first part.  Have a look at the official descriptors for IELTS Task 2 Writing (public version) here, under Task Response, and look for the words “tangential” or “addresses the task only partly.”

How to fix Paragraph Two

1. Have a short (4-10 words) topic sentence. A topic sentence tells the reader the main idea of your paragraph. See Have a look at the official descriptors for IELTS Task 2 Writing (public version) here, under Coherence and Conclusion, and look for the words “clear central topic in each paragraph.” 
   Multinational companies have several disadvantages.   OR There are many reasons why people oppose multinational companies   OR   Multinational companies face many criticisms.
2. Have different kinds of sentences. Have some short sentences and some  longer sentences. Use different sentence structures.
3. Simplify, simplify, simplify.

Shorten/Simplify

You wrotea 37-word monster here in Paragraph Three which has to be broken up:

    On the other hand there are many evidences that prove the multinational companies are a benefit for each country, in a way they provide employment opportunities, import knowledge and experience and make fortune for their share holders.

Here’s one possible rewrite of all of Paragraph Three using a standard 7-sentence layout (Topic, Idea 1, more information, Idea 2, more information, Idea 3, more information)

Topic: However, multinational sentences can also benefit a country.  Idea 1: First of all they provide employment. More information: When companies such as Microsoft, Toyota, Intel or Pfizer build plants in a country, jobs are created for hundreds or thousands of local people and for related industries and services. Idea 2: Second, multinational companies often bring extensive expertise in technology and business. More information: Processes and policies practiced in these companies can spread to local industries and boost their efficiency and work practices.  Idea 3: Finally, many multinational companies invest heavily and are a rich source of tax and revenue for the host country. More information: Countries such as Ireland or Malaysia benefit extensively from the presence of American or Japanese multinationals. Exports increase, employment falls, and other direct investment is attracted.

Conclusion

The conclusion is a little odd: you have some new information and some of it is definitely off topic. Just summarize and give your opiinion, and don't add anything new.

Overall, Rshdwork, use much shorter sentences, particularly for topic sentences. Try to use a simpler 3773 layout (read more about 3773 and 35553 layouts here), and have only ONE idea per sentence.  Aim for about 300 wods max.

You can check average sentence length, word count, and many other useful statistics by using one of the two readability links at the top of this page-  this one at read-able.com, or this one at online-utility.org.  Your average sentence length is 30: you need to get this waaaaaay down to between 12 and 15 words.  If you copy-and-paste your current essay into the first link at read-able.com you will see that it gets a very poor readability score. Shorten and simplify and you will be fine.

Thanks again to Alison for her comments!

One of the main characteristics of the current century is the widespread existence of multinational corporations in various economica (economic) sectors. Many think that multinational companies and their product will hurt (harm) the society eventually. This essay will challenges the topic by examinging both cons and pros(feel like the "cliché") of this phenomenon.

Specialize:——do not use those sentences that can be used in thousands of essays.

For example, you wrote:

This essay will challenges the topic by examinging both cons and pros of this phenomenon.→

This essay will challenge the view that multinational companies do more harm than good by listing some strong and positive evidence.

 

Thesis sentence—— to give your opinion in the introduction can contribute to a good essay. You have no thesis sentence in this part. The topic asks "Do you agree or not". You should answer it with a thesis sentence.

For example，you can say：

It is for sure that multinational companies are to some extend causing negative impacts, but their positive effects to economics do exceed.

Surely there are many forms of expression. It is up to you. The most important thing is to write a thesis sentence.

    One of the main characteristic of the current century is widespread existence of multinational corporations in various economical sectors. Many think that multinational companies and their product will hurt the society eventually. This essay will challenges the topic by examinging both cons and pros of this phenomenon.

    One of the fundamental requirements of establishing a multinational activity is the acceptance of the fact that the society shall prepare itself for welcomming many foreign individuals. People who are opposed to this trend believe that the host nation usually could not impose its own culture to the foreigners and therefore the host nation could gradually accept many unwilling changes. Dissidents also claim that the main purpose of multination’s investors is to find a target market in the host nation and thus be able to sell as much of their products as possible. Extremist oppositions even argue that this type of establishments are only search for solutions to outsource more of their products so they won’t help in any way for domestic employment either.

    On the other hand there are many evidences that prove the multinational companies are a benefit for each country, in a way they provide employment opportunities, import knowledge and experience and make fortune for their share holders. There are many examples of the beneficial side of this case like how Japan have had a big progress in the last century or how the North Korea is going to develop their country through the structure that this flexiblity have created for them so far.

    Sure there are flaws regarding this model but its hopefully solvable If the governments for instance in case of outsourcing, supervise their business by means of policy making and legislations and diminish the plague of outsourcing which sure is one of the main disadvantage of having multinational companies in the country.