Variable Input

Hey there, sorry for the dumb question, but all I want is:

In the Toolbar a Box where I can input a value (Integer would work)
-> Blender to save that value (as x1 oder y2…)

Found great tutorials but none about that basic thing.

It would make me unbelievably happy if you could help me!!

ID properties, for single objects like objects, meshes, bones…

bpy.types properties for all instances of a type:

Thanks very much, great tipps