A new washer should come with all of the attachments needed to hook it up to the faucet but If you get a machine that is not new then most likely you need the faucet adapter to hook it up to the sink.
The faucet adapter is pictured in the image below and is part number 3374592 and can be obtained from the following link:
Your faucet should have a piece that you can unscrew to access the filter screens. Some specialized designer faucets may not allow the faucet adapter to be screwed on.
I hope this information helps to resolve this problem but submit another question with any additional details for further assistance.