Add Approval Link to Salesforce Email Template

Salesforce Approval Process merge fields can be inserted into Classic Email Templates using the Available Merge Fields panel. The steps below show how to locate and copy the Internal or External Approval URL merge field into a template.
You can use the merge field {!ApprovalRequest.External_URL} or {!ApprovalRequest.Internal_URL} by performing the steps below in the email template.

Access Classic Email Templates in Setup

• In Lightning Experience: Gear icon > Setup > Enter Classic Email Template in the Quick Find box
• In Salesforce Classic: Setup > Enter Classic Email Template in the Quick Find box

Steps to Add the Approval URL Merge Field

1. Select the Email template desired.
2. Select Edit HTML version.
3. In the Available Merge Fields panel, select Field Type as Approval Fields.
4. Select Field as Internal Approval URL or External Approval URL.
   1. The Available Merge Fields panel shows Field Type set to "Approval Fields" and Field set to "Internal Approval URL", displaying the merge field value {!ApprovalRequest.Internal_URL}.
5. Copy and paste the merge field value into your template.

Notes

• Approval process merge fields can be used in email templates, but not in mail merge templates.
• Because email notifications to a queue are not intended for an external audience, any instances of the merge field {!ApprovalRequest.External_URL} in the email template are sent as the equivalent internal URL.
• Merge fields/links populate the Record Id when the template is used for an Approval Assignment Email Template, but if the same fields are included in a template used for an Email Alert, the record ID at the end of the URL will not populate.