But suppose I print Bitcoin on clothes, is this legal?
If Bitcoin is not banned in your country, you are free to have the drawing anywhere. If you like, customize cloths in Bitcoin logo, it is not bad at all. Even in country like Nigeria that only the Central Bank is against Bitcoin, not the senate, no bill passed that makes it illegal, not also bad.
If possible, I would consider having some matching accessories together.
This is actually a big project.