An SSL (Secure Socket Layer) certificate is required for the conversation between your website and a visitors browser to be secured. It’s now best practise to load all sites over https:// rather than http:// – your visitors will see a secure padlock in their web browser and can be sure that data they enter into your contact form or purchases from your online store are secure.
Diffusion Hosting offers free SSL certificates from Lets Encrypt™. You can issue these yourself from within your hosting cPanel. You will need your cPanel username and password to access this directly, or you can access cPanel from within the Hosting section of your Client Area.