Apple - How to bring up the virtual keyboard on iOS when a Bluetooth keyboard is connected?

Long press the arrow in the keyboard menu bar (or whatever this thing is called) to bring up the keyboard:

Although this is an old thread, I’m sharing this with you - just in case it’ll help somebody: If you’re using an Apple wireless keyboard, you can use the eject (top right) button to show up / hide the virtual keyboard. To switch input language, use the "Fn" (bottom left) button. Since this is very helpful and since iPad pro Smart Keyboard is probably the most expensive keyboard in the world, this key is of course missing on it.. Great, especially because as far as I know there not no other way to start dictation (microphone button)...

Open Bluetooth settings, disconnect from the keyboard is quicker than unpairing the keyboard entirely. If that works for your specific keyboard, you can use it - if not, you’ve already got the fastest method of disabling Bluetooth entirely.