A shared list means the grocery list is everyone's to add to, and anyone who's at the store can see it. It's built into the Reminders app, and it takes about two minutes.







Siri adds to a list by name, so give the list a name you'd actually say. In Cassie's house the store list is called Need From The Store, and "add milk to Need From The Store" puts it there.
Anyone you share the list with can add items and check them off.
The free library has an automation that opens your store list by itself when you arrive at the store. The Automation Kit goes further — screenshot a recipe, and its ingredients land on that same list.