You can check the general email settings in the platform by navigating to Admin > Settings > Company Details > Email details.
Allow Email Sending?
Here you can disable sending emails from the platform by changing the setting to No.
Auto Send Certificates
Here you can disable auto-sending certificates from the platform by changing the setting to No.
Send Emails to Pending Users?
Here you can decide if pending users should receive emails. A possible use case is that you are using the Standard activation method and not all users have activated their accounts yet. If you have this option turned to Yes, it means e.g. pending users will be receiving notifications about assigned modules or email News Feeds.
Here you can choose which activation type should be used as a default one when you activate users at the platform. If you would like to learn more about activation methods, check one of these two articles:
Change User Activation Method
How to Activate Users
Important! Each time you change any settings here make sure you scroll down to the bottom of the page and click 'Update' to save changes.