How to lock my kid Iphone but authorise him to visit a specific website and use phone and whatsapp only

Thank you Limnos for trying to help me.

I understand that's the documentation and I will give it another try and translate everything to my wife.

Still, In my opinion all this is way too technical and is totally miss-adapted to the user targeted, a parent(s).

While this complexity offers (I hope) great flexibility, sometimes users needs simple things with terms they understand.

For exemple, "Do you want to turn off Downtime".

It takes a second or a third reading to fully understand what means which is very confusing as you (parent) want to turn on or off access to the device.

"(un)Lock the device" is way much simple and doesn't refer to a double negation !

More than that, for some reason on Iphone it doesn't work immediately and I had to ask my kid to restart his Iphone to have it set. (don't have this is issue with family link)

And it goes for almost all options and functionalities.

Everything is way too much complicate and where is the device location ?

I understand I need to open Find my Iphone.

Why do I need to open another app (validate the access and answer more questions) ?

I'm a long time Apple aficionado (I still have a Mac Lisa XL) but this... 🤯