This question already has an answer here:

When is "z" pronounced "zee" and when "zed"?

From what I found out "zee" is AmE and "zed" is BrE. And in abbreviations the letter is always pronounced "zee" like in LZ (landing zone).

merged by J.R. Jan 17 '18 at 1:34

This question was merged with When do we pronounce Z as “zed” and not “zi:” because it is an exact duplicate of that question.