How can I earn by writing? The thing is that I very like to study, read books, and consume new ideas. ?

Oh... Dude, I'm going to be honest: I don't see it happening. Not ever.

For one thing, your English (vocabulary, grammar, spelling...) is very poor as well as your language skills (punctuation, capitalization, sentence structure, etc.). Secondly, it is rare for writers to make money writing. -The vast majority pay their bills by holding a "regular" day job and they write on the side. It's not even a day job for the vast majority of those who are repped by an agent and have published numerous novels. Some self-publish, either through online platforms or through a vanity publisher, but they're lucky if they manage to sell a few units for no more than a few bucks at best.

In order to be one of the rare cases, you'd first need to master the English language. Correct. But since you're so far off, it'd require many years of studying, reading, and writing. Even your average native speaker can't write at the level required to get paid for it.

Basically, you need to be better than a native English speaker. Then, you'd also need to develop your language skills, hone your craft, and work your *** off for many (additional) years like any other person who dives into creative writing. So even if you mastered English, you'd still need to become a good writer. To get good at the craft itself. You get good at the craft only by practicing A LOT. By reading hundreds of books and by writing every day, even when you don't feel like it. Even if you're busy, uninspired, or tired. It is said that your first million words don’t count. Meaning, you don't get good until you've written a million words... That's not one, not two, but SEVERAL novels or many many short stories. In addition to that, if you ever want to get traditionally published (not self-published), you'd also need to learn all about the business end so you don't make beginner mistakes or get scammed.

Something like that would take you at least 2 decades. Only then you might be ready for a lit agent, to get published, or to be paid. And that STILL doesn't mean you'll ever land an agent, get published, or be paid. And if you do, that STILL doesn't mean you will make enough money to be able to pay your bills without a "normal" day job.

Be honest with yourself: Are you willing and capable of working this hard for so long for this little chance? Is this goal even realistic? Are you going to make some sacrifices? Are you going to wake up earlier, before going to work, or stay up late so you can write a few pages? Because that's what writers do - they have a day job too, remember? Are you going to give up some of your weekends and time with your family and friends? Are you going to try and find every little opportunity to write? Are you going to rewrite and edit each novel a million times before moving on to the next one? Do you have the passion for it in the first place or is it just the fantasy of doing something with your ideas?

The reason I don't see it happening is because the vast majority of people have ideas for books and such but they can't do all this hard work. They just can't commit, at least not for long. They start out all excited, but that excitement fades once they realize it's harder than they initially thought. And so they come up with excuses, such as being busy or writer's block, before quitting completely. That's how it usually goes. The vast majority can't even complete 1 novel, let alone master the craft and write numerous novels.

I honestly don't think you have the work ethic or the ability. You're already using work as an excuse. Writing is hard as it is, regardless of your language. If you want to try to become a writer anyway, I suggest that you pursue it in your own language. -Your chances of getting paid will get just a little better. But for the record, I think you're with the vast majority, not a rare case.

By the way, I'm only assuming you're talking about novels. Your question was far from clear, which only emphasizes your weaknesses. Either way, the answer still applies whether you're talking about creative writing, screenwriting, playwrighting, journalism, content, or any other field of writing.

Encouraging you to follow that path would be wrong.  Speaking as a modern language prof -- from everything I've seen here, you don't have the foreign language aptitude necessary to get paid for your writing.  

I'm reminded of the student determined to major in Spanish despite having only a C average in his Spanish courses.  I finally took him aside and said:  "Why would anyone hire you to teach Spanish when they can hire applicants with averages of B and better?"

You have to be realistic.

Sure. That is what authors do - earn money by writing.  However, except for a very few notable exceptions, authors make very little money from their books. One pro I know expects to make $8-10,000 per book, IF it sells well.  And, they don't always.  As this represents about 2-3 years of work, you would need another job as well.

Okay, but the real question is, are you an author?