All VTEX stores must activate the HTTPS protocol in all their pages until April 20. This change will make your website much safer for your clients, especially because all data transfers will be encrypted.
Besides all the benefits in terms of information security, the HTTPS protocol ensures that your store will be better ranked by Google. Their search algorithm indexes secure sites over the ones which doesn't use HTTPS. This means that if your store has enabled the protocol throughout all it's pages, it will be easier to find by potential clients.
Enabling HTTPS is also a key requirement to use VTEX's new CDN, as announced here. Available since October 2017 the new CDN will be mandatory starting in April 20th, and will enhance your website's performance.
To enable HTTPS in your whole store, follow the instructions of this VTEX Help Article.