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.

How to upload a shirt design to the Roblox Store? To upload a shirt design to the Roblox Store, you will need to have a Roblox account and be a member of the Builder's Club.

Roblox allows players to freely personalize clothing items, allowing them to express themselves and stand out from others.