You can customise your Mastodon profile page to include text, images, animations and links to websites, other accounts etc. Links can also be verified as belonging to you, which makes them handy in verifying your identity.
More info on doing all of these at:
You can also expand your introductory material by creating a post about yourself using the hashtag #Introduction, and then pinning it to your profile. (More info on pinning: https://fedi.tips/how-do-i-pin-my-posts-on-my-mastodon-profile/)