Installing the SSL
Once you have purchased the SSL, it needs to be installed. This is done by deciding which domain will have the certificate. If you have a hosting account with unlimited domains and maintain more than one website, you’ll need to choose which is getting the new SSL.
Using a Plugin to Make the Necessary Changes
Using a plugin can take a great deal of the work out of using the SSL for your site. Many of these will automatically make the necessary changes once your certificate has been purchased. Some will set up the site just by activating the plugin without requiring additional input from yourself. Here are a few of the best SSL plugins for WordPress:
We recommend Really Simple SSL
This plugin requires no additional setup outside of installation and activation. It will automatically make the changes to the .htaccess file if the SSL is detected on your site. You can also view the configuration settings of what has been controlled by the plugin.
Plugin Link : https://wordpress.org/plugins/really-simple-ssl/