My inquiring mind wants to know, how the hell do you make a call from an i pad?

My granddaughter (not quite 11) called me at work wanting to know if she could order some Warrior Kitty (?) stuff on my credit card. I no sooner said yes get Nanna to help than she was about to hang up. I asked how she called when my ph. Is with me and her grand moms ph. is charging? She said she used her I pad she got on Christmas. WTF? Either I’m Old School or kids these days are techno wizards. But then I had to get the 5 year old to show me how to close out an ap last week….