These join code cards for google classroom have directions on one side for students on how to join Google Classroom, and a place to put the join codes for each classroom on the other side. I used these myself when students had their drive through textbook pick up. I printed them on colored paper, laminated them, and added them to their textbook bag, so they could add their google classroom before the school year started.

Made on Google slides, so it is completely customizable.