If you’re on a computer or laptop, they’ll show up on your profile like Noon said. But I’ve noticed that achievement badges won’t always show up if you’re on a mobile device. For example, I’m on my iPhone right now and this is what I see if I scroll to the bottom of a wiki:
I can see the badges that I’m working towards, but any badges that I’ve already earned won’t appear like they normally would. I’ve never used an iPad for Fandom, so I don’t know if it’s the same for you or not.