Custom form in the user post area

I have searched and searched for nearly a week and cant find what i want.
My new wordpress site will allow people to signup and become an author, so when they would like to post, i have a couple of site links like youtube and spotify link i would like them to post.
It would be nice somewhere in the post area for them to have a box a form box to paste the links needed in to, then i could replace the links with the code needed from the plugins to make them show on the website.
eg https://www.youtube.com/xxxxxxx i could replace as httpv://www.youtube.com/xxxxxxx with the user having to know what to do.
dont want custom fields have tried magic fields, pods cms, simple forms, well pretty much all out there.
I am sure there is a simple answer
User form in the user area not a form on the website just in user area
hope someone knows the answer