I would like to apply two different textures on the same face. I a window textures over which I would like to put a letter texture. I watched many tutorials but many are old. Moreover trying to apply a different texture on the same face after UV unwrapping seems to be impossible. To add clarity I am adding images.

ok, all I want is those purple bars to disappear as shown in the image. I tried everything I simply couldn't achieve it.

[Note to moderator: I checked for this over the stack overflow many are just old and difficult to understand I would like the answer for blender versions 2.8+]