Advisability of putting any phone number on the internet is highly questionable. Not even sure of putting a phone number on a kid's shirt, but the idea was to design a shirt to put mom's cell phone number on it just in case child gets separated or lost while on some outing. To add your phone number to this shirt, click on the "Customize it" button. Then click on "Add text." You can change the size and style of text. I'd recommend making it smaller than the default size and using the arrows to position it just right. Then, I trust, if you just order your customized version and don't publish it or make it public, your phone number will just be plastered on the shirt and not all over the internet.