How to set up field code with letters (not numbers)

[ABK]

Making a legal document, with Exhibit A, B, C, etc. at the end. Have to
insert and delete those pages at times, and don't want to have to keep
relettering. (Can't use numbers.) Can I do this with field codes?

 

[Suzanne S. Barnhill]

If you're talking about page numbering, just choose the A, B, C option for
numbering. If you're talking about captions, use Insert | Reference |
Caption. If you're talking about heading numbering, see
http://www.ShaunaKelly.com/word/numbering/NumberingAppendixes.html