The title of your paper will be the first thing that a user sees. It's important to have a clear and concise title for your paper, and that the title on Academia matches the title of the paper as it appears found elsewhere on the internet or printed journals.
The title that you pick will also show up in the URL/link of the paper. If you edit the name of the paper, the updated name will then begin to appear in the name of the paper.
Your old links will still work, even if you change your paper's title. There's no need to go back and update them.
To edit the title of your paper, first go to your profile. If you aren't on your profile page to look at this information, here's how to get there. hover over "edit" under the paper you wish to change the title of, then click "title."
Then, write the new title you wish to include for the paper, and click save!