if you choose pre-packaged fabric printer sheets you need to read all of the packages- and follow the instructions --choose the one that is (right) for your project-
some of them are made more for wallhangings
there is also Transfer sheets where you print the image-then iron it onto your fabric- (like t=shirt decals)
there are a number of different ones- but with all of them you really need to follow the instructions for The one you choose-
also use good quality-permenent ink- some ink cartridges say right on them---washes out! buy good ink- and follow the instructions for the best results. pigma ink is best.