Firstly, make sure you have ssh access to the server (dev, test and/or prod). Your ssh command looks something like this: ssh user@your-website.com or ssh user@100.230.222.122. Drush alias works by using this username and domain/ip address combination to login to the server and execute the command and then return back to your command line. In your project root, create a drush folder and inside it, create a sites folder. Now you put your site alias config in that folder. Name it something like project.site.yml. So your aliases defined inside it would be something like the following:
dev:
root: /var/www/html/dev-website/web
uri: your-website.com
host: your-website.com
user: ubuntu
ssh:
tty: 0
So your alias here would be @project.dev. You can test this by running drush @project.dev status from the project root folder. The above config is for a server with Linux user named "ubuntu". If you want the drush command to be interactive you can set the tty to 1.
Here's the folder structure.
project-root/
|- web/
| |- modules/
| |- themes/
| |- index.php
|- drush/
| |- sites/
| | |- project.site.yml
|- composer.json
