If you try and print your own decals, then a laser printer is best, as inkjet inks come off in water, so you'll need to coat those first in a clear finish before soaking the decal.

You can't print white or metallic colours on a clear backing (unless you have special ink/toner cartridges) and pale colours don't work if they are to go on dark backgrounds either as the ink isn't opaque enough. So anything white or pale needs to go on white decal paper. And as that is basically white paper, you'll need to cut around the lettering if you just want a white or pale colour logo.