My met withjoining this platform

Okay, this place advised my friendmy friend recommended this place.

"This place advised my friend" means that this website is the one that did the advising to your friend.

Also, "advise" isn't a verb that can be used in this way. To "advise" means to gently suggest to someone that they do something.
"My friend advised me to use this place."
"I would advise you to stay away from that cave."

I would use the verb "recommend" instead.

What about me and why I'mam I here?

"I'm" --> "am I", because this is a question.

I have'm level A1 and whant to go up a level up ¶
My goal is B1 forso that I can work in an IT company ¶
I'd like to be Fa frontend Ddeveloper.

If we were talking about a general field, like "IT", "software development", or "animation", we would leave out the indefinite article 'a/an', like you've done here. "I want to work in IT."
However, we are talking about an IT COMPANY. So we should use an article. In this case, 'a/an'. "I want to work in an IT company".

Job titles like "frontend developer" are usually lowercase. You'll only capitalize it if the job title itself is part of a title (of an article, for example), or you might capitalize names of a company, like "a Google executive".

My met with tJoining This pPlatform

Okay, this place advised my friend. My friend advised me to use this place.

I have level A1 and whant to level up .¶
My goal is B1 for work in an IT company. ¶
I'd like to be Fa frontend Ddeveloper.

My met with tIntroduction to This pPlatform

"My meeting" would be correct English, but "meeting" is typically reserved for meetings among people. I proposed a natural alternative, capitalized according to title rules.

Okay, this place advisedwas recommended by my friend.

What you wrote would indicate the website directly gave your friend advice (as if the website was a person).

Alternative: My friend advised me to try this website. (This is pretty formal)

I have a level A1 (in English) and whant to improve my level up .¶
My goal is to get to B1 forto work ifor an IT company .¶
I'd like to be Fronte-End Developer.

We wouldn't typically say "level-up" in terms of improving language skills; it's really associated with video games. I would say "improve my skills," but specifically you can say improve your level or attain a higher level.

That's all 😁