When we send email from external email applications, we can use Email to Salesforce to automatically relate those emails to our Salesforce leads, contacts, opportunities, and other specific Salesforce records.
When composing, forwarding, or replying to an email, we enter a special Emails to Salesforce address in the BCC field (or any other recipient field). Salesforce receives a copy of the email. Depending on our configuration, Salesforce adds the email to the Activity History related list of the record whose email address matches the recipient’s email address, or to the My Unresolved Items page. From the My Unresolved Items page, we can manually assign the email to a record. Unassigned emails also appear in our open task list.
To Enable this features, please follow this steps :
Step-1 : Navigate to setup, and in quick find box search for Email to Salesforce
Step-2 : Under the Email Administration click and open Email to Salesforce.
Step-3 : In this page, Edit and Check the Active Checkbox to enable this feature.
once enabled this feature it will be activated. Please follow more steps to find the Unique email .
Step-4 : Click My setting from your profile picture, once opened click Email section.
Step-5 : Then Click My email to salesforce, we can see the email with long mixed characters. this is the email.
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Click here : for reference