Q: WSD or Web Services on Devices??

Hi MrsMolly,
 

Thanks for visiting Apple Support Communities.
 

I see you're trying to scan from your new Epson All-In-One printer/scanner in OS El Capitan. If you connect the scanner to your Mac using a USB cable, you can scan using the Image Capture application. For more help with this, see the instructions in Mac Basics: Using a scanner.
 

If you're using the scanner wirelessly or over a network, you can check the following Epson page for setup and help information: Epson America, Inc. - Support: OS X El Capitan Support
 

Sincerely.