Let's Encrypt is a free, open source security and privacy application that provides automated and secure certification authority (CA) service to website owners. It is a global initiative to make online experiences more secure by providing a free and easy way to obtain and install X.509 certificates, which are used to enable secure communication over the Internet. With Let's Encrypt, website owners can easily obtain an SSL/TLS certificate to enable HTTPS on their website. Let's Encrypt provides certificates with a 90-day validity period, and the certificates can be renewed automatically. In addition, Let's Encrypt also provides additional security features such as HTTP Strict Transport Security (HSTS) and Domain Name System Security (DNSSEC).
Their support is awesome. Any novice can easily install the certificate correctly with the help of live chat.