Helpme, Please!!

I am an online new translator of a German company. I don't know about how to do my payments. At the moment, I cannot be self-employer, therefore I need a special certificate or documentation and I don't know what. The German company is Humangrid, maybe you know about it or you are also an online translator, but not self-employer.

If you know something about this case, tell me. Any information is very wellcomed.:rolleyes: Thankss!!