Last time we bought a house, we did basically everything on our phones, including tapping our way through the closing paperwork on one of these platforms. Easiest time by far—we’d used them for parts of other house purchases, but had never done the whole thing that way before. These sorts of platforms also take care of notifying everyone when stuff’s done, maintaining an todo list for signing, sending reminders, verifying you didn’t miss spots that need a signature or initials, and making sure everyone who needs access to the docs, has it. They’re really nice.
Anyway, if you just want to draw a signature on docs standalone with only local software and none of that other nice stuff, the good solution on a desktop OS isn’t mspaint, but Preview. Works directly on pdfs, can generate a fancy sig or let you draw your own, signatures re-usable and available in a drop down menu next time you need to sign something.