Enable Apache2 Headers Module
sudo a2enmod headers
Enabling HSTS for Apache2
sudo nano 000-default-le-ssl.conf
<VirtualHost *:443>
Header always set Strict-Transport-Security "max-age=31536000; includeSubdomains;"
# or
Header always set Strict-Transport-Security "max-age=31536000; includeSubdomains; preload"
</VirtualHost>
