In Scrum and other Agile methods, a common way to manage feature requests is with User Stories. I’ve been teaching people about User Stories and doing workshops with teams for a long time. Out of that work, I’ve created a very simple PDF User Stories and Story Splitting reference sheet that might be handy. Please feel free to download it and share it. This document is something that I explain in-depth in my Certified Scrum Product Owner training seminars.
There are a number of sites out there that include some details that are left out of the reference. Please see, for example, “Patterns for Splitting User Stories” by Richard Lawrence. See also the great foundational article on “INVEST in Good Stories” by Bill Wake.