In August 2018 Goggles app stopped working: Google now redirects users to Google Lens app or, for incompatible phone, to Google Photos which includes Lens' features.
With Google Goggles you can perform web searches by taking a picture rather than typing in text. It can be used to search based on the pictures of logos, text, barcodes, street signs, landmarks, and more.
Lens is a valid alternative to Goggles because it offers extremely similar features to Goggles. It tries to identify the content of the photo and give you useful search results and actions that you could take on that data.