Pleeeaasee help me correct this small part

My dream is to get involved completely in this ambit. [Sorry, but I cannot deduce what you mean by "ambit." If you meant "ambition," then the whole sentence needs to be rewritten. If you meant "field" or "profession," those would be better word choices...] I believe the only way to help the world is through education. A more humane education, one centered in the children's wellbeing. (Or, a child's...) As for the future. I truly/honestly cannot say what would make me happier. However, at this moment of my life, after completing my Masters studies, I would like to either work as a school headmaster or intervene (or participate...) in the political aspects of the educational system within my country. Regardless, wherever the course of my life eventually takes me, this degree can provide me with the proper foundation and tools that I need to be successful. accomplish an excellent job in the area.
Mi goal is to keep learning in order to be able to do a make changes in to society based on scientific knowledge, yet changes that are firmly grounded with humanitarian and social values.
It is towards this goal and it's resulting experience that I am applying to this program in the sincere hope of being selected and being able to play a small, but vital, part participate in the changing of education.
Thank you in advance for your attention, (Or, consideration...) and I await waiting a positive response y send you a most cordial greeting.

Hi Carin. While I have done what I could, without more context,  it is hard for me to know what direction to take. Certainly, one or two more drafts should be done. The words highlighted were misspelled, and in all honesty, were such an application presented to me, I doubt that I would finish reading it. I am not trying to be cruel, but these are simple, but preventable, mistakes that may serve to prevent your acceptance, so please be more diligent. Your greeting should come at the beginning of your letter/application. I will be glad to help you, so please feel free to contact me should you so desire. I hope that both these edits and comments help you. J.

[this is good, I've only changed the minimum]

My dream is to get involved completely in this ambition. I believe the only way to help the world is through education. A more humane education, centred on children's wellbeing. As for the future, I could not say what would make me happiest. In this moment of my life I have not yet decided whether after completing my master's studies, I would like to work as a school headmaster or intervene in the educational political aspects of my country. Whatever the course of my life may be, this master's degree can provide me the tools I need to accomplish an excellent job in the area.

My goal is to keep learning to be able to perform a change in society based on scientific knowledge with a humanitarian and social sense.
It is for these dreams and experience that I apply to this master's course/program in the hope of being selected and being able to participate in the reform of education.
Thank you in advance for your attention, and I await a positive response and I send you a most cordial greeting.

Pleeeaasee help me correct this small part

My dream is to get involved completely in this ambit. I belive believe the only way to help the world is through education. A more humane education centred in the children wellbeing. As for the future, I could not say what would make me happier. In this moment of my life I have not yet decided if after completing my masters studies, I would like to work as a school headmaster or interveen (........) in the educational political aspects of my country. Whatever the course  of my life may be, this master can provide me the tools I need to accomplish an excellent job in the area.
My goal is to keep learning to be able to do a chance in society based on in scientific knowledge with a humanitarian and social sense.
It is for this dreams and experience I apply to this master in the hope of being selected and being able to participate in the changing of education.
Thank you in advance for your atention, and waiting a positive response y send you a most cordial greeting.