Hello , i'm beginner in this forum

and want to ask about
how can the traders earn bitcoins

?
thank you
May I warn you that this is very hard, to earn money from trading! I see that you are a beginner, so if someone told you go and trade Bitcoin and alts and you will make money then they have lied to you.
If you are a professional Forex, stocks, etc.. trader, you know how to read charts and signals that market sends you then OK. You can make money while trading BTC. If you have no experience with trading whatsoever I strongly advise you that you don't trade. Read, learn about Bitcoin, research about markets and how all this is working instead.
Good luck!