Save the location of mobs and load these mobs to the saved position?

Is it possible to save the location of certain mobs and load these mobs into the saved position?

I made the interface, added two buttons "Save" and "Upload". By clicking on the "Save" button, my specific mobs will be saved, and by clicking on "Upload", those mobs that were saved will appear in the same place where they were.

I tried to do it myself, but I couldn't do anything, for me this is the most difficult part of my mod.

I agree, it sounds complicated. Maybe variables are needed here, right?