First, you print (using your DTG machine, with textile ink) to DTF PreTreat Sheets cover your print with DTF Transfer powder, and then heat press it to your Garments or Textiles. You can either print in COLOR, for transfer to WHITE textiles, or you can print 1 layer of COLOR then 1 layer of WHITE, if you're transfering to DARK / BLACK textiles.
But what's the purpose of DTF Transfer if the purpose of DTG is, by definition, Direct To Garment, and with DTF Transfer you're introducing a transfer sheet?
Traditiona transfer printing been around for ages, and specifically used in the heat transfer or sublimation print markets. So what are the benefits of DTF Transfer? There are a few actually, and they are significant:
DTF Transfer allows for transfers to dark shirts (due to white DTG ink) - something regular heat transfers can't do
DTF Transfer result in more breathable prints, smooth to touch, and flexible - something regular heat transfers can't do
DTF Transfer do not requiring cutting out the image on the transfer - something regular heat transfers can't do
DTG TRANFER result in more vivid colors than heat transfers
OK, so the above shows the substantial advantages that DTF Transfer has over HEAT TRANSFER (or even SUBLIMATION).