Yes it is included.
By getting Droplet on DigitalOcean, you are getting VPS (Virtual Private Server) with root access. Root access is administrator rights on server, with that you bascically do whatever you want on server.
You are accessing Droplet via SSH, and you can learn how to do it in How To Connect To Droplet with SSH.
Your Droplet will include OS you selected on creation or you can select One-Click app which will include Ubuntu and selected apps already installed.
You can take a look at available apps on One-Click Apps page.
If you decide to go without One-Click app, DigitalOcean have great Tutorial base which will help you install any app.
In case you need help, ask here, we will try to help you :)
If you have recently created a DigitalOcean Droplet, and you are new to working with Linux servers, you will need to learn how to use SSH to connect to and manage it. SSH, which stands for Secure Shell, is an encrypted network protocol that is used to for, among other...