What are the codes for Final Fantasy VII to Duplicate items and Material?

Answer 1

To duplicate items, you'll need the W-item materia (find it in the Midgar revisit). Equip it, and go into any battle. Select W-item to open the menu, then select the item you want to duplicate and choose a target.

It'll go back to the menu and you'll have to choose a second item, choose any random item to select (use O), it will bring up the pointing hand to choose a target, DON'T SELECT a target: Cancel instead

You can do this as many times as you want, taking note of the 99 limit on each item of course. (The first item you choose will be the one duplicated).