While you do not have to use what Richard recommends QR Droid's QR code generator it is a great resource.
Below is a quick video on how to create the QR code for parents. Below the video you will see an example of what the scan will create in the user's device.
Example of what happens when a parent (or user) scans the QR code created by this site.
Click here for a generic form I created using Google Forms (see embedded picture below). The form will be copied directly into your Drive and can be altered in any way you wish. Please let me know if any questions.
As always, any questions please let me know!