Q.Pussy willow
Beautiful wen I bought it started to grow green leaves but the leaves are turning brown and brittle. It is still in original pot should I plant it in the garden. Don’t want to lose it please help

Yes, I would plant out your tree, it is likely stressed and may be needing more water in a container.
This article will help you with planting and care guidelines.
https://www.gardeningknowhow.com/ornamental/shrubs/pussy-willow/growing-pussy-willows.htm