Open Roblox Studio
Create or choose a clothing template
Use an image editor to design the clothing
Save the design as a PNG file
Upload the image to Roblox
Go to the Create page on Roblox
Select Shirts, Pants, or T-Shirts
Click Upload Asset
Choose your PNG file
Pay the upload fee if required
Wait for moderation approval
Equip the clothing on your avatar or sell it in the catalog