You should have an SSL certificate for your domains to give your users/visitors the best and secure experience.
And here, you can learn how to install SSL for your domains for free on your control panel!
Just login to your control panel and select the domain that you want to install an SSL certificate!
Click on SSL/TLS Certificates
And now, you'll be redirected to another page! Here you can see different SSL Providers, you may also purchase premium SSL's from here! To install a free SSL certificate, just choose Let's Encrypt and click on Get it free.
Here, you need to enter and choose some important things, in order to install an SSL certificate.
You need to enter your email address to receive notifications about SSL expiration and other things. And if you want to use wildcard SSL you may select Secure the wildcard domain (including www and webmail)
And also select Assign the certificate to mail domain to secure your emails. And finally, click on Get it free and that's it. Your SSL has been installed.
For few domains, you may need to add a TXT record to verify the ownership of the domain!