Hello! Use top solder mask layer and bottom solder mask layer.  Regards, Markus Virtanen HW / Electronics Designer

This may help you understand how to use the SolderMask layers. [https://oshwlab.com/andyfierman/how-to-make-an-aperture-in-the-solder-mask](https://oshwlab.com/andyfierman/how-to-make-an-aperture-in-the-solder-mask)<br> <br> Remember that a shape in the SolderMask layers **removes** solder mask so that the shape creates an aperture in it.

I finally found the solution!! Just right-click on the trace, then click "ADD", then add the solder mask region. 

For clarity: The post above by Omid Alavi refers to EasyEDA Pro and not EasyEDA Std.