Transition to formula milk

My baby, now 9 months , is exclusively breastfed and started solids at 6 months. She is now at 3 meals per day plus evening snack along with breastmilk. I now want to slowly stop breastfeeding and move her to infant formula but she is rejecting all the brands i have tried so far- nan, similac, hipp… I even tried mixing with her solid food so that she gets used to the taste but she becomes nauseous and shows vomiting symptoms. Please advise how to move her to formula .. tips and tricks are welcome🙏🏽🙏🏽