Add a hyperlink to an image or text in email templates #inSalesforce

To hyperlink an image in an email template :

App Launcher | Email Templates | Click on All Email Templates and select an email template from the list | Open the template then click on Edit | Click on the Source button and include the following codes:
<a href="Link URL">
<img src="Image Address" />
</a>
Or, you can click the image within the template then click the link icon and paste the URL.
Click Save.

To hyperlink a text in an email template :

App Launcher | Click on Email Templates | Click on All Email Templates and select an email template from the list | Open the template then click on Edit.
Click on the Source button and include the following codes:
<a href="Link URL"> "TEXT" </a>
Click Save.

Reference: https://help.salesforce.com/s/articleView?id=000320277&type=1