OCs or online characters are characters of the MLP: FiM Fandom make.
Mosy of the fandom make their OCs to be their ponysona. A ponysona is an OC that you make up that is alike the person who made it. For example, the OC to the left is my ponysona. She is just like me because she is an excellent drawer.
How the OCs are Made
Well, first of all, they have to get an imgae of them. Most people use the pony creator made by Genral Zoi, who is a girl. Some people use the pony creator on the hub website or draw it themselves. I prefer the pony creator made by Genral Zoi. Next, you have to name it. You have to make it unique.Don't use ponies' name from the show, unless your the voice actor for this pony, but its least likely a voice actor would make an OC. Try to think of something that someone has never made. If you want to look for names that are taken so it doesn't seem that you are stealing it, go to Mlp Forums and look at the OCs. Most of the Mlp Fandom is there. Lastly, don't forget its cutiemark. Try to find somethig that relates to the name.