Purpose

To disable the "Invite some teammates to make Confluence more fun!" emails. 

Solution

1. Go to Confluence Admin >> Scheduled Jobs.
2. Disable the scheduled job: scheduledjob.desc.onboardingNumberOfUsersCheckJob.
3. Next go to Confluence Admin >> Manage Add-Ons
4. Search for 'onboarding' in the text box.
5. Choose 'System' from the drop-down menu.
6. Expand all modules.
7. Disable the 'Onboarding Number Of Users Check Job(onboardingNumberOfUsersCheckJob)' module.