He works at a consulting fairm, and frequently change thes his job to the another foirm to increase his salary.

This is a great sentence! There were only a few minor spelling and punctuation errors.

I’ve been alsoalso been studying English and investment, but it’s very normal for me.

As a native speaker, I would put "also" before "been studying."

The most ambitious person I know is my friend.

This is technically correct but it would make more sense as "my friend, their name". This is just so you know, obviously don't put their name online.

He works at consulting farm, and frequently change the job to the another foirm to increase his salary.

form=shape
firm=company

I'm also ambitious, I’ve been also studying English and investment, but it’s very normal for me.

I'm not 100% sure I understand, this is my guess as to what you mean.

He works at a consulting fairm, and frequently change ths from one job to the another form to increase his salary.

A "farm" is a large space where you grow plants or raise animals, usually for food.

"Another" is a contraction of "an other" (with the indefinite article). So "the another" doesn't sound right. You would have to either say "the other" or "another" (by itself).

I’ve been alsoalso been studying English and investment, but ithat’s very normal for me.

When using "I've been", adverbs go in the middle, not after. "I've just been ______", "I've really been ______", etc. This is because "been" itself is a verb: it is the past participle of "be".