To become a Roblox shirt tester, you need to have access to Roblox's shirt creation tools, which are available to all users. However, to sell your designs, a premium membership is required.

How to Make T-Shirts in ROBLOX T-Shirts are the easiest clothing to make in ROBLOX. Create an image that’s ideally 512x512 pixels and then upload it to ROBLOX via the Asset Manager in ROBLOX Studio.