The best way to allow leads to opt out of emails from Zoho CRM is by using Unsubscribe Forms.
Follow these steps to create Unsubscribe Forms:
- Go to Setup > Developer Space > Webforms > Unsubscribe Form.
- In the Unsubscribe Form page, do the following:
- Enter your website address in the Return URL field.
- Click Generate HTML code.
- Copy and paste the generated HTML code into the HTML editor and save it as an HTML file.
- Click Finish.
Your leads can click on the unsubscribe option available in your email template, enter their email address and proceed. This will immediately enable the email opt-out field and you'll no longer be able to send emails to that record.
Read more in detail about generating an unsubscribe form
here.