Do you mean in your description or what ?
I can't put links and stuff like that in my about me section
Actually I understood it now whats the problem .You need to be 90 days old member in order to insert pictures or links or games .You need to be 90 days old on this site ,after that you can do that i guess .The same happening with me too .
And its only 21 days that you are here ,so I think that you need to wait for 90 days as I am also waiting for those 90 days to be completed lol .

Looks like you have to be a diamond, platinum or gold member at least once to be able to insert links, images, ... I'm just guessing!
I remember reading this on support.chess.com somewhere

Oh so? I rarely read support.chess.com.
Yep, I do recommend reading the support pages. They're not long and tedious to read either and very easy to navigate through

:c
help me
I believe the other suggestions are correct and your account isn't old enough for adding links. I don't know for sure if it's 30 days or longer.
Some options are premium only:
https://support.chess.com/article/672-how-do-i-fill-out-my-profile
:c
help me