A simple technical writing question
When I was in college I took a technical writing course. There was a form that we were taught to use consisting of a table with cells labeled with letters of the alphabet. The purpose of the document was to establish and conform to conventions--which words to use, which font to use, etc. I want such a form for a project I'm working on, but I guess the world has moved on because I can't find much information about it.
What's the name of that form, please? I don't want anything elaborate like software I need to learn, just something I can slap together in Libreoffice will do.
Thanks much!