How to add an SSL certificate to Wordpress and switch from HTTP to HTTPS
Choose an SSL certificate from https://www.123-reg.co.uk/ssl-certificates/
If you don’t know the steps to do so, the article regarding on how to assign a newly purchased SSL might help.
Once the SSL certificate has been assigned and issued, you may want to configure WordPress to use the SSL certificate and force redirect HTTP traffic to HTTPS.
A simple way would be installing the Really Simple SSL plugin which will take care of the redirection rules in the .htaccess file and additional mixed content.
Navigate to your WordPress dashboard and click on Plugins > Add New.
Type Really Simple SSL in the search box then locate the plug-in.
Click Install and then Activate and then a new page will load.
Click on Go ahead, activate my SSL! And that’s it.
Please note: You might need to log in again after you click on Go ahead, activate my SSL!