Open your DealMachine mobile app or log in with your computer to https://web.dealmachineapp.com
Click the menu button in the top left (mobile only).
Click Default Mailing Options
Select an option for the field "Sending Mode"
Click "Update Default Options"
Note: the default sending frequency will apply to all new deals added. You can adjust the sending frequency for existing deals by opening the deal, clicking the "Options" button within the Mailing Addresses section. Click Repeating Mail and set accordingly.