In the Estimate Details tab
1. Scroll to the bottom left to add Documents
2. Click to upload or drag and drop
3. You can categorise the documents into folders
4. Click "Upload file" to attach
5. On the right is the Notes field
6. Type in your note
7. Click "Save"
8. The note will date and time stamp with the logged in users details
9. There is a trash can to delete notes
In the corresponding job you will see any documents and/or notes added at the estimating stage, and the ability to add more.