Welcome

You can just say welcome. Some people where I live, in the northern US just say 'yep' but I think that's rude, so would not advise it.

In American/Canadian English, we almost always say "You're welcome" and not "welcome." I have noticed that British English speakers sometimes say "welcome." Some other common responses are: No problem. (this is the most common nowadays) My pleasure. No worries. It's nothing. (for a small thing!) A bit longer, but common: Don't mention it. It's not / It wasn't a problem. It's the least I can do. (say this if you owed them a favour!) Hope that helps!