You’re supposed fo buy baby’s water for formula?

What??? I’ve been boiling tap water all this time since 2008 when my daughter was born. I have 5 kids and was able to breastfeed 2 of them but for the rest of my kids I’ve boiled tap water for their formula. I thought that’s how you’re supposed to do it but I’ve seen videos of moms buying baby water for their formula 🤔