If big you might have to re inforce the studs or structure first. Outside would be plastering you need to lath with at least 60min paper wire scratch and brown then stucco. Inside would probably be drywall, figure out your drywall size and cut middle of stud to stud, screw off tape and feather out joint, texter and prime. Sand your flaws before paint
Honestly, use Google for YouTube "how-to" videos. There isn't much you can not find on home repair.
Is the hole is drywall? If so there is drywall patch and repair kits you can buy.
Thanks! Your answer is awaiting moderation.