Check out my initial set of scripts in that More link above. They're very simple and they work perfectly with respect to extrusion.
If you imagine a very long (unattended) pause, you might need to tweak things. A long pause would probably result in drooling hot-enough filament slowly onto the part. In that case, you'd likely want to retract 5mm before and extrude 5mm at the moment of truth when resuming. Another safety mechanism would be to move the assembly over toward the home position in some way and then back.
Following that thread, you can see that others want to cool things down and then bring them up to heat on the resume.
In my own case when I was first printing, I noticed that ALL print jobs started off with a deficit of available filament. The initial line never laid down, only getting started perhaps 10mm into it. Looking back on those days, the initial gcode prefix provided by my printer manufacturer was to blame since they didn't understand that audit I described before.
M82 sets the extruder to absolute mode and G90 sets the other motors likewise to absolute mode.
M83 sets the extruder to relative mode and G91 sets the other motors likewise to relative mode.
Most pause/resume script examples assume that your motors and extruder are both in absolute mode so be careful what you snag from the Internet. Relative extrusion is something new so not all of the tutorials and exampls have caught up yet.
In fact, new work is being done in Marlin at this time to include some logistics to make all of this easier. One of the authors is now working on that. A new Mnnn command of some kind will return the current state of the motors, making it easier to create a bullet-proof pair of pause/resume scripts.