You can set up email notifications for you as a merchant and for your customers as well.
As a merchant you can be informed of new charges, disputes, payouts and fraud warnings that happen on your account. Additionally it is possible to set up a reminder for dispute evidence 7,3, and 1 day before dispute evidence due date
Email notifications for your customers will inform them about their successfully processed charges or refunds they have received.
This article explains how to set this up.
Email notifications for merchants
Using the drop-down menu in the back office's upper right, select the account to which you wish to set up the email notifications.

Click on the account name.
Click on Profile.
Pick the email notification that you would like to receive under Send me emails for.
Click the Save button.
Email notifications for customers
Using the drop-down menu in the back office's upper right, select the account to which you wish to set up the email notifications.

Click on the account name.
Click on Account settings.
Pick the email notification you would like to send your customers under Send customer emails.
Provide your company name, website and contact email. This will make it easier for the customer to recognize the charge.
Click the Save button.