Why are there numbers next to my iPhone and iPad in my devices list in settings?

If you don’t change the names of new devices when setting them up, the setup process automatically adds a number in parenthesis to identify it from previous devices with the same name.

You can go to Settings ➡️ General ➡️ About ➡️ Name, and change it to anything you want.

That usually means your network is misconfigured, or that you have multiple devices sharing the same name.

Multiple devices with the same name can potentially happen when migrating contents to a new iPhone or iPad too, should both still be in use in parallel while transitioning.

If your network is misconfigured, each device connecting can detect a matching host name already connected to the network (itself), which can mean there’s a loop in the network wiring somewhere. How that happens depends on your particular network equipment and its particular cabling.

If you are no longer connected to a network with a misconfiguration, or to a network with duplicate host names in use, you can reset the device name to what you want using Settings > General > About > Name