Utilities

apache2ctl – Apache HTTP server control interface

restart	Restarts the Apache daemon by sending it a SIGHUP. If the daemon is not running, it is started.
fullstatus	Displays a full status report from mod_status.
graceful	Gracefully restarts the Apache daemon by sending it a SIGUSR1. If the daemon is not running, it is started. This differs from a normal restart in that currently open connections are not aborted.
graceful-stop	Gracefully stops the Apache httpd daemon. This differs from a normal stop in that currently open connections are not aborted.

apache2ctl graceful

Modules

a2enmod,a2dismod

a2dismod php7.0
a2enmod php7.3

systemctl restart apache2

phpenmod,phpdismod

phpenmod mbstrings

Random

SSL Certificates

LoadModule ssl_module modules/mod_ssl.so

Listen 443
<VirtualHost *:443>
    ServerName www.example.com
    SSLEngine on
    SSLCertificateFile "/path/to/www.example.com.cert"
    SSLCertificateKeyFile "/path/to/www.example.com.key"
</VirtualHost>

https://httpd.apache.org/docs/2.4/ssl/ssl_howto.html