Additionally, handwriting in margins would work. If you need a lot more room to edit, using the back of the page or stapling a blank page to the page in question would work.
I think the type of revisions you’re doing is also going to affect how you revise.
Developmental edits - you’re probably going to be typing up a second manuscript (second pass).
Line edits - writing in the margins, white out. Probably would eventually want to type this out as a third pass.
Proofreading (assuming you do your own proofreading) - probably the same as line edits, but hopefully there are less edits. This would be your fourth pass if you did one round of each edit (counting the drafting as the first pass).
Never used a typewriter before, but if I was going to, that would be how I would plan and attempt to follow through with revisions.