Send your guests a link to their customer portal in an auto email.
You can add the link by using the tag {{ 'hyperlink text here' | customer_customer_portal }} when creating or editing an auto email. The tag cannot be found in the dropdown list of reservation properties. The link enables guests to upgrade their reservation via widgets with additional products or services before their arrival.
Read more about email variables and tags: Email variables for auto emails and templates
Find out more about adding widgets to the customer portal: Adding widgets to the customer portal