My website actually shows the password page for any user that connects to it, since my product will be ready in few days.
The visitors can register their email address in order to be notified, and then the website displays "We will send you an email right before we open!"
I was wondering how this email will be sent ? Will I be able to modify its content ? Or do I have to send it manually ?
On the shopify admin panel, there is a lot of "Remove password protection" button, in order to remove the password page.
Maybe the server will fire some emails when I click this button, but I actually don't want to try right now, because I don't want any of my customer to receive an email when the website isn't ready to sell.
People that use the form will go into your customer list so they're ready for you to use in a email tool of choice. Mailchimp is a popular option for sending emails to customer groups. It's an email that you'd craft and send manually so won't be something that Shopify will do on your behalf.