Clothing problem

How to help my daughter with her clothing problem.
My daughter just turned 6 in July and since may she has been giving us issues with getting dressed and picking out clothes. It’s gotten 10x worse since school started last month. We have been picking out clothes the night before to prevent fighting and breaking down in the morning but it doesn’t work. Everything in her closet she gives a reason to hate it so she doesn’t have to wear it . We even let pick out all her school outfits to make her like them more and want to wear them but she since she won’t wear them and they still have the tags on it. I just don’t know what else to do. I talked to her doctor and she said she would give over it soon but I don’t think she will . I just need advice