Changing link letter to word e.g:- /t/ to /name of the category & modify or remove /c/

Please tell me if I am incorrect with my assumption. It sounds like you want to change the structure of the URL for SEO purposes.

If not, apologies for the assumption. But either way, the topic of changing the url structure has been discussed before here:

If you have the advanced skill level to edit Discourse’s source code, then Sam’s answer may be what you seek: