Ready to hang is a sales or marketing term used to describe a painting or art print that can be hung up on a wall and displayed immediately, without the buyer having to do anything. (Other than having a nail in the wall to hang the painting on.)
There is no standard definition of what to expect with something defined as "ready to hang". The painting may be framed or unframed. If framed, it may or may not be under glass, depending on what medium was used to create the painting. About the only thing you can expect is that it will have something on the back you use for hanging it on a hook, such as a tag, hook, or wire.
