It depends on what type of link you are fixing. I've attached three other questions below that might help. Personally though, I would go to whatever the link was for (Google Doc, website, etc. copy it again and then paste over the existing link.
Hope this helps!
Hello jkearney Welcome to the Canvas Community. Thanks for posting your question here. I agree with @courtney_wagner ... we need some additional information from you. What kind of broken link are you trying to fix? Is it a link to another website outside of Canvas? A link to another part of your course? A link to a document? A link to an external LTI tool that you're using in your course? If you could please come back to this thread to provide some details for us, that would be helpful. Thanks.
In December, you asked for help fixing a broken link. On the same day as your post, @courtney_wagner and @chofer followed up with a few more questions. Since you haven't returned to the thread, I hope that means you found a solution! (That would be awesome!) For now, I'm going to mark this question as "Assumed Answered", but it will not prevent you or any other Canvas Community member from commenting. If you have a few minutes to explain how you resolved the issue, that would be great! That way, if anyone else has the same question, they could learn from you!