It’s all too easy to end up with more Bluetooth devices connected to your Mac than you can shake a stick at. Apple devices will likely have sensible names, like Magic Mouse 2, but what if someone has given you a device with their name in it? Or you’ve ended up with a device called something really random like f023cp37. Fortunately, macOS lets you rename most Bluetooth devices, including pointing devices, keyboards, earbuds, headphones, and speakers. First, make sure your device is currently connected. Then open System Preferences > Bluetooth, Control- or right-click a device, and choose Rename. In the dialog that appears, enter the new name.
What about on iPhone or iPad? There is nothing you can do about that just yet. But iOS and iPadOS 14, due out this fall, will finally allow you to customize the names of your Bluetooth devices.