The source of the file (at https://github.com/certbot/certbot/blob/master/certbot-auto like Stephen wrote)
Download and run the latest release version of the Certbot client.
certbot-auto is a wrapper around certbot, as explained later in comments:
USAGE="Usage: $BASENAME [OPTIONS] A self-updating wrapper script for
the Certbot ACME ...
You need to tell Google that your new domain name is your canonical domain name for the content on the site, otherwise Google won’t index the new domain since it is duplicating content.
You can move to a new domain name by using 301 redirects from each page available on the old domain to the equivalent URL with the new domain. (Implementation of this ...
There is a plugin for WordPress called SSL Insecure Content Fixer that will automatically change any calls to content from http to https.
You can also use a find-and-replace plugin or use wp-cli to do a database-wide search for "http:" and replace it with "https:" but you run the risk of breaking links to sites that do not have SSL enabled.
If you have a secure page (HTML delivered via HTTPS) that calls an image or any resource from a source that is not secure, the page will now be considered overall not secure. ... Mixed content affects the way your webpage is displayed by browsers.
WordPress stores the full image URL in its post database.
So after turning the website to HTTPS, you have to ...
https://www.bybe.net/cloudflare-enforce-ssl-redirect-http-https/ has the full details.
To redirect to HTTPS, you need add a "Page Rule" for http://*example.com/* with the "Always Use HTTPS" option from the settings.
To redirect to www you need three "Page Rules":
http://example.com/* -> https://www.example.com/$1
https://example.com/* -> https://www....