Gazelle has three fields you can use. By default they are called: Custom 1, 2, and 3. but you can edit the name and function of these fields for your own purposes.
FROM THE WEB APP
Step 1: Go to a client record
Step 2: Go to 'Additional Info'
Step 3: Expand the fields to show these custom fields.
Step 4: (Optional) Edit the custom field names. Go to Settings > Company Profile > Custom Client Fields to edit the field titles.
Step 5: Done!
To edit the field titles Settings > Company Profile > Custom Client Fields
FROM THE MOBILE APP
Step 1: Tap on a client record
Step 2: Scroll down and tap 'Show More' to view any data in the custom fields.
Step 3: Done!
NOTE: Editing the field names / titles can only be done from the web app at this time. However, once changed this will be reflected in your mobile app.