Custom Field Formula that Adds One Month to a Date and Displays it in 'Month DD, YYYY' Format

To add a month to a custom formula field, follow the steps below:

1. Navigate to Customization > Lists, Records, & Fields > Transaction Body Fields
2. Edit your custom field
3. Uncheck the Store Value checkbox
4. On the Validation & Defaulting subtab, enter the following formula under the Default Value field:
to_char(add_months({trandate},1),'Month DD, YYYY')
5. Check the Formula checkbox
6. Click Save