Any work restrictions will be printed on her BRP.
For the fine detail, see paragraph 319D(a) of the immigration rules. There are only two prohibited or restricted types of work. Sub-paragraph (iii) restricts work as a Doctor or Dentist in training and paragraph (v) prohibits working as a professional sportsperson.
I do not give immigration advice. I refer you to Immigration Rules, guidance, other online content and to your sponsor.