PrestaShop allows us to work with its pages in secure mode thanks to the implementation of HTTPS. First, to have PrestaShop with HTTPS, you will need to have an SSL certificate contracted and installed on your domain.
If you have contracted it with us, we must install it on the domain and it will be done. Or we can generate one with Let's Encrypt
Then, we will have to enter the administration of PrestaShop, and go to Store settings (or Shop Parameters if it is in English) > General
Inside, the first option is Activate SSL, and we click on Please click here to check if your store supports HTTPS. to activate HTTPS in the store.
When we click, the website reloads and the option to Activate SSL already appears. We click on Yes in Activate SSL and click on Save. This way, we already have our store with HTTPS active.
To apply it to all pages, and not just to the administration or cart, we must select Yes on Activate SSL on all pages.