LinkedIn, Indeed, job boards, companies’ career pages, career fairs, etc.

I need some advice that better then "just apply" or "jsut work on your skills" or "jsut custimize your resume for job posting"

Lower your expectation and get some internship or something, it doesn’t pay as well as normal jobs but it should still pay and you get the work experience needed for your resume

specific reason u get rejected?

"decided to proceed with other candidates"

You don't know theory

And its true - you may ask me simple javascript question and I don't answer on it

There, you know your weakness. Work on it.

I even don't solve some simple task (I forgot how it names website where people solving code channelges)

For web development knowing JavaScript is a must

You need to work on your skills to make yourself capable enough of solving them, I wouldn’t want to hire someone struggling at simple tasks that they are supposed to smoothly sail through either because you will be doing those tasks everyday at work.

I think contribute to some project its great idea

as joulev said if you really want to start a career as a developer you should maybe look at the basics and work your way up

a good starting point would be to have at least good degrees and have finished internships in that region

or try your luck somewhere locally and in firms or companies who don't really have that field but maybe are interested in having someone working on that