USA Social Security Question, adult disabled person.

[jtees4]

My daughter is an adult, and disabled, but she is high functioning. She has always worked in her adult life. The last few years she has been working more and more, her job loves her and keeps giving her more hours. She lost SNAP and Medicaid Benefits awhile ago, which was fine because we know it is strictly income based and she can get them back. She got a Medicare Plan through the exchange. She only gets Social Security at this time, she used to get other things (we were also in a different State).
1. How much is she allowed to make on Social Security? (I have seen differing answers).
2. More importantly, what happens when she goes over?

Any help would be appreciated, or help with showing me exactly where to look.
Thanks so much.