In your email template:
Select the word/phrase that will be used as the unsubscribe link.
The word toolbar will appear. Click on the Hyperlink option
Configure your Unsubscribe word or phrase as shown below where:
Link Type: URL
URL: [unsubscribe] (this is the replacement tag commonly used when configuring SendGrid for the unsubscribe.)
Text to display: Choose what you'd like to display as the text for the link
Using the unsubscribe tag in HTML source
If you're using HTML source for your campaign emails, the [unsubscribe] tag can be added in there as part of a URL.
Example of an HTML link using this replacement tag as the URL: