Let's Encrypt SSL Certificate is a Certificate Authority (CA) that enables you to create a free SSL certificate for your domain.

You can install it easily through Plesk by taking the following steps:

1. Log into myTophost Panel and select Plesk Login next to the plan you are interested in installing the SSL for.

2. In Websites & Domains tab, choose Let's Encrypt.

3. Type your email address (it may be used in emergency announcements or in case of key loss). Check Include if you want to install SSL for www.yourdomain.com and select Install.

4. After completing the installation, the service will be successfully installed on your domain within 60 minutes.