categories

Hello, I have a question with the categories in the url, I want to have a url like this: domain.com/ colors / blue, when a user enters the blue category which is the url that will exit but if someone writes domain. com / blue, I do not want anything to be seen is to say a 404 error

Theme doesnt control slugs or urls. You likely need to look at a plugin or write custom function to adjust your permalinks.

You could likely try the redirection plugin to redirect

Site.ooo/blue
To
Site.ooo/colors/blue

I think in many cases wp may try to redirect there anyway as long as no post starting with
Site.ooo/blue-post-name

Not sure if that helps or not.