It helps to read wikipedia. It is rather a trend to change to htttps://
Server setup
To prepare a web server to accept HTTPS connections, the administrator must create a public key certificate for the web server. This certificate must be signed by a trusted certificate authority for the web browser to accept it without warning. The authority certifies that the certificate holder is the operator of the web server that presents it. Web browsers are generally distributed with a list of signing certificates of major certificate authorities so that they can verify certificates signed by them.
Acquiring certificates
Let's Encrypt, launched in April 2016,[21] provides free and automated SSL/TLS certificates to websites.[22] According to the Electronic Frontier Foundation, "Let's Encrypt" will make switching from HTTP to HTTPS "as easy as issuing one command, or clicking one button."[23]. The majority of web hosts and cloud providers already leverage Let's Encrypt, providing free certificates to their customers.