You can indeed use sublimation paper on T-shirts. Depending on the type of sublimation ink you use, you will need to make sure that the T-shirt is either polyester or a poly-blend or that it has been coated with a poly-spray. Many sublimation inks require polyester or a poly-coat to bond with while in their vapor state.  To use sublimation paper on a T-shirt, simply print the design onto the sublimation paper using sublimation ink, and then apply the paper to your desired substrate and use a heat press at the required temperature and for the right amount of time to press the design into the material.