Install & Enable HTTPS on Apache Server

First of all, you need to have a website that can run under http. This tutorial is about Apache2, and other servers may have similar settings.

1. Get a free SSL certificate.
   Now Let’s Encrypt offers free SSL certificate service. So we need to register an account. Then, after landing you can apply for a free SSL certificate. Finally save the requested certificate locally.
2. Configure the Apache2 environment
   This will automatically install the SSL plugins required for Apache2.
   

   sudo a2enmod ssl
   
   sudo a2ensite default-ssl

   Create a default SSL site that will be in /etc/apache2/sites-enabled/ to generate a configuration file.

   In /etc/apache2/creating two folders

   cd /etc/apache2
   
   sudo mkdir ssl.key
   
   sudo mkdir ssl.crt

   Upload *.crt to ssl.crt folder, upload *.ssl to ssl.key folder.
   Next, we start the configuration default-ssl.conf file

   sudo vim /etc/apache2/sites-enabled/default-ssl.conf

   In which the following attributes are changed

   SSLCertificateFile     /etc/apache2/ssl.crt/2_***.crt
   
   SSLCertificateKeyFile /etc/apache2/ssl.key/3_***.key
   
   SSLCertificateChainFile /etc/apache2/ssl.crt/1_***.crt

   After the change is successful, restart the Apache2 service

   sudo service apache2 restart

   Finally, try to access https://YourDomain

3. Enable https by default
   On .htaccess file, add
   

   RewriteEngine On
   
   RewriteBase /
   
   RewriteCond %{SERVER_PORT} !^443$
   
   RewriteRule ^(.*)$ https://YourDomain/ [L]

   After the creation is complete, change /etc/apache2/apache2.conf

   AllowOverride All

4. Enjoy