Is it permissible for her to use the Zakat and Sadaqah money that was given to her to take a certain exam, for another exam, or to open a private clinic, or must she inform the one who gave her the money about that?

Your sister is not permitted to take from zakat funds to spend on her university studies. Education is not among the essential needs that allow taking from zakat, and a debtor (gharim) is someone who owes a debt. If it becomes clear to her that taking zakat is impermissible, she must return it to its owner so he can disburse it according to its legitimate channels, or he may willingly forgo it and give an equivalent amount instead. As for charity (sadaqa), its scope is wide, and she is permitted to benefit from what she has taken from it and dispose of it as she wishes, unless the donor specified a particular purpose for the charity, in which case his intention must be observed.