Disable Ask to Buy notifications from appearing on my iMac

Like many things Apple, I find things not very intuitive. I keep getting Ask to buy on my iMac, not on my iPhone. I have looked up everything I could find to disable it on my iMac but still, it goes to my IMAC! Please tell me HOW TO STOP GETTING NOTIFICATIONS ON MY IMAC. I only want them on my phone EVER.

thanks