Common finishes include zinc/nickel/chrome plating, passivation, powder coat, and conversion coatings. Each changes appearance, corrosion performance, and sometimes dimensions (build-up in holes).
Specify thickness ranges or call out a governing standard when procurement needs apples-to-apples comparisons.
Hydrogen embrittlement relief bakes may be required for high-strength steel after certain plating processes—your stack should mention process-sensitive alloys.
For mixed-metal assemblies, document galvanic compatibility or isolation strategies to avoid field corrosion.