How hard is it to change a two prong plug outlet to a three prong?

Yes you can! But if you do not have the proper tools, please call an electrician! Safety first - you and your family are far more important. Here are a few links for you. Good luck.

https://mrelectric.com/blog/how-to-replace-two-prong-outlets-with-a-three-prong-outlet

https://www.thespruce.com/upgrade-2-prong-outlet-new-gfci-1824671

https://youtu.be/oTuknHridYI

You could always hire an electrician to change a couple, and watch what he/she does, and do the other ones yourself if you feel comfortable.

Call an electrician for your safety and that of a future homeowner. Whole house could need rewiring.

It's an easy job. www.thisoldhouse.com/ideas/replacing-two-prong-receptacles. If the outlets are in the kitchen or bathroom, you will need to install GFI outlets

You can still buy 2 prong plugs or you can install a 3 prong if there is a ground wire or if the if the wiring was done with metal conduit (pipe) or by installing a GFCI plugs lastly a GFIC breaker can be installed at the breaker box to cover a whole circuit

We buy two prong to three prong adapters....come two to a package....not expensive at all.