You can get a free certificate for your domain from Let's Encrypt.
※Please note that the installation will result in an error if your domain is not ready for name resolution.
1. Log in to the Control Panel.
2. Select "WebHosting Plesk" from the menu on the left.
3. Open the MORE TOOLS.
4. Select "Let's Encrypt".
5. Specify the email address that will be used for emergency notifications and recovery of lost keys. The contract owner's email address will be registered by default.
6. Specify whether or not to include an alternate domain name for the domain and each selected alias. We recommend that you turn this one on.
7. If you have multiple domain aliases, select the ones you want to include in the certificate.
8. Click "Install" to obtain and install a Let's Encrypt certificate for your subscription.
9. From the Hosting Management screen, click "Hosting Settings".
10. Select the certificate you have created from the list of "Certificates" under "Security", and click the "OK" button at the bottom.
A certificate will be installed. You can use this to enhance the security of your site.
If you want to set up Wildcard SSL/TLS, you will need to set up a TXT record separately.