Take your equipment (it must be 8 1 grade green or above) to the equipment forging department for signature, and the attack equipment should be signed with grade 2 or grade 3 silver.

Other equipment shall be signed with second-class or third-class hard cover. Before signing this, you should go to the grocer to buy a soul crystal moon bottle (with silver) or crescent bottle (with silver card) for binding.

It seems that equipment below level 80 cannot be signed.