Steps for altering your avatar’s appearance in every Roblox experience, from adding and removing items to changing your skin ...

Open up the Roblox app, then tap on the middle icon at the bottom of your screen. Then make sure to tap on the "Customize" tab.

To start, check out these handy templates which ROBLOX themselves has created. If you right click and save these images, you can use them as a guide on how the clothes should look once you upload ...

Much like most things on Roblox, you will be making this yourself from scratch, so you'll need to design a t-shirt in an image and then upload it to Roblox.