This is the ultimate solution for redirecting all URLs from HTTP to HTTPS in Drupal. 

HTTPS is the latest encryption standard for the web. It’s more secure than HTTP, which was once the standard. Most browsers currently support HTTPS, and it’s becoming more popular as more websites switch over. Drupal is no exception: we recommend that all URLs be redirected to HTTPS. This will make your website more secure and protect your data from being intercepted or stolen.

Here is the 301 redirect instruction, how to do it on your site.

First you have to create a blank file and ftp it to your server in public html folder if you are using CMS - Content Management Systems or just the root folder of your site.

The file name should be

.htaccess

so be careful to put the . in front of the filename or it would not work.

And this is to put into your htaccess file