wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -
sudo apt-get install apt-transport-https
echo "deb https://artifacts.elastic.co/packages/7.x/apt stable main" | sudo tee -a /etc/apt/sources.list.d/elastic-7.x.list
sudo apt-get update && sudo apt-get install filebeat
sudo update-rc.d filebeat defaults 95 10
sudo systemctl enable filebeat

Configuration:

sudo vim /etc/filebeat/filebeat.yml

comment-out elasticsearch lines (2)

uncomment and configure logstash lines (2)

SAVE.

Enable filebeat apache module:
sudo filebeat modules enable apache

Configure custom logs in apache2.conf and any enabled sites

reboot.

Confirm filebeat service is running.
Confirm data is appearing in filebeat