You could say: She bought herself a pair of shoes or She bought a pair of shoes for herself

"She has bought a pair of shoes" is a perfectly fine sentence. Adding "for herself" (or any other person) is also valid. "She has bought a pair of shoes." "She has bought a pair of shoes for herself." "She has bought a pair of shoes for her friend." All of these are perfectly valid English sentences. Please let me know if I didn't answer your question. Thank you.