There are two ways to get a t-shirt, the simplest is creating one. You can do that by going into the T-Shirt Creator and making your own shirt.

The other way to get a T-shirt is buying one, many T-shirts are V.I.P shirts, which may or may not give you privileges at certain places. Others can be decorative, for instance, you can buy shirts like the classic Bloxxer shirt made by ROBLOX to make your character look cool!

See also