How to control email tracking in Salesforce?

By default, Salesforce adds hidden image links to emails to allow for tracking emails. Depending on your business requirements, you may want to disable email tracking for invoice, dunning reminder or account statement emails sent from your org.

To do so:

1. Click to enter Setup, then navigate to Feature Settings > Sales > Activity Settings.
2. Deselect the checkbox Enable Email Tracking.
3. Click Submit.