Pretty much any phone made in the last couple of decades should work just fine. It's just a small few older ones that have a proper bell ringer inside that may struggle to work with the new digital system.
If you already have a landline telephone, you should be able to plug it into the back of your BT/EE Hub and have a working phone just like it previously was.
You can get yourself one of the BT Digital phones if you would like though. This will connect wirelessly to your hub so you don't need the phone and router in the same place. And you will also benefit from features like HD Voice when calling supported lines.
Make sure that your EE Order does actually include telephone service though. A lot of their best offers are for broadband only, and it costs extra to add the landline.