duplicate and reverse?

I remember there was a way of duplicating shift D that also put it the other way round.
duplicate a left boot and get a right boot.

quote “Mirror while in edit mode “M” will give you a mirror command.”

that don’t seem to work!

The mirror command for object mode is Ctrl+M Then hit Y, X, or Z to mirror it to that axis. Good luck!

thanks
for anyone reading this.
duplicate first.
then on the duplicate Ctrl+M.
then x, y or z.
it will mirror the duplicate. ( not add another one) assuming you want two items, left and right.