https://www.theverge.com/2018/6/4/17426668/google-lens-app-play-store-android

Google has released a standalone Lens app in Google Play so now you can have yet another way to access the feature if your Android device doesn’t currently offer it. The Lens app has the same functionality as Google Lens does elsewhere: it uses artificial intelligence to deliver information about captured images, such as of clothes, books, and buildings. Once you open the app, it brings you to a viewfinder where Lens looks to identify nearby objects.

Even though you can download it, the Lens app does not seem to be compatible with all Android devices. For example, it will work with Samsung Note 8, but not with the Samsung Galaxy S8 Plus. Other users have reported the app not working on Moto Z Play, Nokia 7 Plus, and the Xiaomi Mi A1. On Google Play, the app says it requires Android Marshmallow and above.