I want to be a singer, how can I sign with a company?

Record your own singing into a demo tape, and then send it to various record companies, because your singing is equivalent to your resume.

Or go to a well-known bar to sing, if you meet a talent scout, you will be discovered.

Or participate in a talent show with a better reputation to increase your popularity first.

If you are very rich, just package yourself and release an album. But I guess this path is basically impossible.

Or it just depends on your luck.