Soldato
Are you at the right workbench? You need a weapon workbench to repair weapons, an armour workbench to repair unpowered armour and a power armour work"bench" to repair power armour.
I don't know what you mean by "use wrap to repair".
What I get is this:
At the right workbench, press space to enter the "Modify/Repair" menu.
Select item
Press T for "Inspect/Repair"
Press R for "workbench repair" (or T again for repair kit repair).
Wrap = scrap (typo)
Ok thank you. I figured it out. What I was missing was pressing the R bit.