How do I report an UTMA withdrawal as a 27 year old? What can I expect to pay in terms of taxes on a withdrawal?

I'm 27 and just found out I have an UTMA account that was established in my name. I'd like to make a withdrawal but don't know if: a) the withdrawal will be taxed, b) what the tax rate would be, c) if there are any restrictions about what I'm allowed to spend the money on, and d) how to report this on my tax statements. Any advice?