I’ve gotten to know quite a few people through distance learning. I am familiar with their voices but I have no clue what they look like. In this case, I can say: “I don’t know them from Adam!”. We use this expression when we don’t know what the person looks like. We would not be able to recognize them if we were in the same room.
When working with mnemonics as a learning technic, I ask my learners to associate Adam to the first man from the Bible. We know of him but we wouldn’t recognize him if we passed him on the street.
Here are a few examples in context :
I have never heard the feminine version “I don’t know her from Eve”. Have you?