Do i need a business license for the square app?

I'm a freelance cosmetologist, still in school, and I'm starting to build my clientele.
I tried downloading the square register app but it asked for a tax ID number, so I gave it my social security number instead. The app wasn't able to register me even though I'm a sole proprieter.

My mom told me I need a business license to get a tax ID.
How do I go about doing that, and if I do, does it cost anything?

Thanks!!

no you don't. the square is attached to your checking account.
registration is glitchy for the square- but we didn't have to give it anything but our account and routing number to use it.