How to approve purchases without an Apple device as a guardian

You're correct, receiving Ask to Buy notifications currently requires an Apple device. While you can set up family sharing and Ask to Buy without an Apple device, receiving and approving requests are limited to Apple devices like iPhones, iPads, and Macs.

Here are your options:

1. Since your daughter has a new iPhone 14, she can utilize the "Approve in Person" feature within Ask to Buy. When she attempts a purchase, she can choose "Ask" which will send a notification to her own device. On the iPhone 14, she can tap "Approve in Person" and enter your Apple ID password to complete the purchase.
2. Add your daughter's father to Family Sharing as a Guardian: Adding your daughter's father as a guardian with his iPad would solve the notification issue, as he could receive and approve purchases on his device. To do this:

Remember that adding him as a guardian grants him parental control over your daughter's account, so discuss and agree on boundaries beforehand.

Apple's ecosystem is designed to primarily send these notifications to Apple devices connected to the Family Sharing group.