Secure Sockets Layer or SSL helps to give your site a more secure structure by creating an encrypted link between the server and client.
You do not need to purchase SSL certificate. Pixpa itself would be applying the SSL certificate on your website.
After you have connected your domain name, Pixpa will review your website and apply SSL certificate to your site.
P.S.: It will usually take up to 24 hours for the SSL certificate to be applied.