The download and install option for iOS 15 is not coming up in my iPhone

To update all of these requirements must be met:

• You must be connected to a Wi-Fi network (and not a personal hotspot) unless it is an iPhone 12 series with an active 5G network connection
• The phone must be charged to at least 50%, and preferably plugged in so it stays above 50% during the update
• The phone must not be in Low Power Mode
• The phone must not be connected through VPN
• The phone cannot be in Airplane mode
• If you participated in the iOS 14 beta you will have to delete the beta profile

So, the option to download iOS 15 is on the bottom, and it also says that you need a word network. If you don’t have one, see if a friend has one.