When editing any sketch one can see two origins; one red and one blue. The blue origin is always there but hidden if you have it set to that. It’s the center of the part file and never changes orientation from the triad in the bottom left hand corner. The red origin changes orientation depending on how your sketch plane is created. Just as the sketch geometry is read by solidworks in polar coordinate the planes are also orientated in them. For instance in the picture below I have created an offset plane some distance from the front plane. The Y-Axis is pointing up and the X-Axis pointing to the right just as the traid in the bottom left corner shows.