My daughter who is an adult and not my dependent helps with our personal business. Can I get a deduction for this?

Only if you actually paid her.  then you could deduct the amount you paid her and she would have to report it as income.  You would also have to issue her a 1099.

If you are paying your daughter you will put the expense on your Schedule C and issue a 1099NEC to her for the self-employment work she is doing for your business.   Or..if you are treating her like an employee---you issue a W-2 and you still put that expense on your own Schedule C.