How to "tag" google photos to search for specific photos?

Question

Google

I actually store a bunch of photos in Google photos, everything is fine, unlimited space, loads quickly, the time scale is also good, but if you take a picture of a document and you need to find it, it's just hell ... there is a "photo description" function, but search for these data does not pass. Who can tell how to be? I somehow stared at evernote but it has a lot of limitations and a problem with photo shrink (I wrote to the support for a long time they confirmed the bug) I don’t know how it’s true now ..
Actually, Google is completely satisfied, but there is not enough sound search, which is strange when you consider who Google is :)