Hi my name is heather I want to know can I claim my 21 yr old sister who is disable, I'm her payee and take care of all her expsenses

Yes, because she is disabled if she provides les than half her own support, and she lives with you at least half the year, then she is your "qualifying child" and you can claim her as your dependent. If she is not permanenetly and totally disabled or if she doesn't live with you, you can still claim her as a "qualifying relative" dependent IF her net income is less than $3,650 and you provide more than half her support.