GNU/Linux Ubuntu 20.04 Epson L366 Printer Setup – Step by step Guide
The linked tutorial shows you step-by-step How to Install Epson L366 Series Printer/Scanner on Ubuntu 20.04 Focal LTS GNU/Linux desktop – Step by step Tutorial.
And to Install Epson L366 Printer on Ubuntu Focal you need to Setup the Proprietary Driver.
Especially relevant: after the Driver Installation to achieve the Printer Setup follow guidance to Add Printer!
Using the Epson Printer Utility Software, you can check Ink Levels, View Error and other Status…
Finally, the guide includes also detailed instructions on How to Get Started Epson Scanning.

GNU/Linux Ubuntu 20.04 Epson L366 Printer Installation Guide