First you'll need to get a Galvanized Upgrade Smithing Template, which can be obtained from mineshafts, village blacksmith or pillager outpost chests. Once you have it, it can easily be duplicated with Zinc Ingots and Tuff.
It can also be created from scratch using a sequenced assembly recipe.
To upgrade your equipment, simply put it in a Smithing Table along with the template and a Zinc Ingot.
Galvanized equipment can also be repaired with Zinc Ingots alongside their default repair material (configurable via tag).
Galvanization is generally more effective on tools than armor. While galvanized tools have 60% more durability, galvanized armor only has about 33% more, however it does have a slightly higher enchantability bonus.
Create (required). For galvanized Steel equipment, you will need Create: Alloyed (optional).
