Argenta allows you to add notes to all constituent types, grants, mission trips, events, campaigns, and other important areas within the system. This is a great way to add additional items that relate to the item you are working on. You can let others know what you are working on or any extra things they may need to know about the item/event/etc. The notes section looks like this:

Anytime you see a notes section click "Add New" to add a new note:

This will open the Add A New Note screen:
This is a free-form area where you can type an unlimited number of characters for your note. You can add as little or as much detail as needed for the note.
Once you have typed all the details needed for the note click the "Save & Add This Note" button to add the note and be returned to the previous screen.