I’m making a game that I have been working on with UE4 for a while. I was wondering when I finish the game, if I can publish it, and make it for PC. I know the game Caffeine is for PC and was made with UE4, and only one person made it. So I was wondering if I could do the same, by publishing my finished product for PC?
Yes, check out docs or other questions on cooking and packaging your project for Windows PC.
What makes you think that you can’t do that? Main target platform of this engine (atleast on this licence) is PC 
most people here use this engine to make PC game with possible perspective on mobile and consoles (which 2nd requires custom licence), there few that mainly target on mobile. Just remember about royalties 