Think about it. You can only fit physical components move footprints on the top and bottom layers. Therefore you can only swap PCB footprints between top and bottom layers. Multilayer pads are for through- hole components (PTH) and so connect to all layers. Single layer pads are for SMD components and so can only go on top and bottom layers and cannot have holes in them (except for the special case of thermal vias about which there is a howto post). There are also a couple of recent threads about vias in EasyEDA and how they connect between layers. Please also search for Example's  howto project called "Elements of a simple PCB".

Sorry, the first paragraph should have been: "You can only fit physical components on the top and bottom layers."

BTW: your post has nothing to do with Solder Mask. Did you mean to ask a different question? Please read the sticky post at the top of the forum about how to ask for help. Thanks.

> Multilayer pads are for through- hole components (PTH) and so connect to all layers. - - - Actually, I'm working only with through hole components so i want the "pads" to be in one layer, sorry to use the term solder mask and sorry if i mixed things up:)

If you have your PCBs made for you by JLCPCB then the default is 2 layer with plated through holes. So every component lead will go through a pad on the component side layer (top) which have a plated through hole to a pad on the bottom layer. You only care about having through hole pads on one layer only (the bottom) if you are etching the board by hand and given the very low cost and exceptional quality of JLCPCB, including plated through holes, solder or ENIG plated pads and silkscreening, why would you want to be working with a single layer, to a much lower standard and having to handle and responsibly dispose of toxic etching chemicals?

This might help you understand what goes into the design of a simple PCB: [https://easyeda\.com/andyfierman/Elements\_of\_a\_simple\_PCB\-e42c7b2a4e17449f821a97d04806aeeb](https://easyeda.com/andyfierman/Elements_of_a_simple_PCB-e42c7b2a4e17449f821a97d04806aeeb)