H1B status is NOT H1B visa
Please note H1B approval status in NOT H1B visa. Visa is needed when you want to enter the border of USA.
If your sister is under H1 B status which means her employer sponsored her with H1B, she is the beneficiary. She should have the H1B action notice showing approval. She should copy the lower portion I-94, which showed the petitoner, beneficiary, and expiration date ect. and staple them in the passport.