c# - Changeable UI

Hi Guys!

I am pretty new with C# and am currently trying to solve the following problem.
My application is created in VS 2019 with WPF. It's basically an app where the user can write texts/dates/numbers etc in input fields and the app will store them in a database. So far, so good.
I am now searching for a way to create some kind of exchangeable UI, where the user can decide which surface he likes most.
The changes can reach from slightly different colors of a button up to a complete rearrangement of the whole UI with different buttons and same buttons in different places etc.
Furthermore, I search for some kind of framework that makes it easy to expand the variety of UIs in the future. So in case a user isn't happy with the currently offered UIs, it should be relatively easy for me to create a new UI that suits his demands.

I would be happy if someone could point me towards a promising direction - many thanks in advance!