Do you have a website link on your profile or in your posts? Have you made sure it is clickable?

You have to have https:// at the beginning of a web link for it to be clickable on here. Without this, people cannot click on the link.

Without https://
example.com

With https://
https://example.com

(BONUS TIP: Advanced users might like to know that Mastodon supports many kinds of link including https://, http://, gemini://, dat://, dweb://, gopher://, ipfs:// and ssb://)