There are only a handful of popular ways to document Salesforce. Here are three for your consideration.
1. Design document
Your team usually needs precise instructions on how to configure the platform. A design document, usually written in Google Docs or MS Word, is a common way to communicate these instructions.
If this document is kept up to date, it’s a single source of truth. The challenge becomes keeping this forever-live document up to date.
2. User stories
When business requirements are broken down into user stories, you’ll often find the specific feature design embedded in the story.
This approach allows architects to only be concerned with the current user story. However newer stories can update or depecreate previous ones, which makes knowing the current state tricky.
3. Elements.cloud
Tools like Elements.cloud can be useful. With Elements, you can extract metadata, and then augment it with additional documentation. In addition, you can leverage their AI to prompt the documentation.
For more information https://elements.cloud/salesforce-documentation/
The takeaway
Whichever approach you take, be sure to use templates to keep the look and feel consistent.