@GraysonEichelbe ...

Auto-saving should be automatic...as far as I am aware.  Text entry assignments use the Rich Content Editor (RCE).  Check out the section on "View Auto-Saved Content" (and the info below it) in the following Guide:

How do I add and modify text in the Rich Content E... - Instructure Community (canvaslms.com)

I'd recommend also typing out your response in an offline capacity using something like Microsoft Word and then pasting it into the RCE within Canvas when you are ready to do so.  This eliminates the chance that text is somehow lost upon submission.  I'm not saying that text is lost every time for every student, but I've seen a few similar questions recently, and this usually what is recommended for these kinds of situations.

Hope this helps in some way.