If you want to create cut lines in outside programs, you will need to use Vector Drawing software to create the cutting lines. (Illustrator, Inkscape - which is free, CorelDraw or Affinity Designer.)
Programs like Photoshop and GIMP are raster based programs, so all they can create (generally) is engraveable results.
There’s a tutorial here that explains the differences to help folks get going quickly with designing for a laser.