Some types of customers have special privacy or security concerns and may therefore request that you don't use any email following features when you communicate with them. You can easily disable these features for specific customers by setting email following options for their contact, lead, or account record. Email following is enabled by default for all records, so you must explicitly disable it when needed.
To enable or disable following for any contact, account or lead:
Open the contact, account, or lead record you want to work with.
Under the Contact Preferences heading, find the Follow Email setting.
Click the value shown for Follow Email to toggle the setting between Do Not Allow and Allow, as needed.
Click Save to save your setting.
Any time you compose an email that includes one or more recipients that do not allow following, the controls for enabling the various follow features are shown as disabled on the email authoring page. When following features are turned off, the message won't include a web beacon (clear GIF), all files will be attached directly rather than linked, and no links will redirect through Dynamics 365. But you can still schedule delivery, and may still see template and delivery-time recommendations.
To view the tracking preferences for all of the recipients of a message, click the View Recipients' Preferences link shown above the body text. A pop-up window opens, showing the name and follow preference for each recipient. From here you can open any contact, account, or lead record by clicking their name in the list.