If the virtual keyboard of iPhone is missing or not appearing as you are trying to type, the problem could be due to an External Keyboard still being connected to iPhone or Keyboard features like Reachability or One-Handed Keyboard being enabled on your device.
In addition to these common reasons, the annoying issue of keyboard missing on iPhone can also be caused due to use of third-party keyboards, the keyboard dictionary being corrupted and other reasons.
iPhone Keyboard Missing or Not Showing Up
Before going ahead with the steps to fix the issue of missing keyboard on iPhone, it is recommended that you restart your device and see if this helps in bringing back the missing keyboard.
If a restart does not fix the problem, you should be able to bring back the missing keyboard on your iPhone by using other troubleshooting steps as provided below in this guide.
Related: Fix: Microphone icon Missing from iPhone Keyboard.
1. External Keyboard
If your iPhone is paired with Magic keyboard, the solution to the missing keyboard issue could be as simple as pressing the Eject Key on the Magic keyboard, which works like toggle; showing or hiding the onscreen keyboard when it is pressed.
The other option is to disable Bluetooth on your iPhone; which disconnects the Bluetooth keyboard or permanently remove the Bluetooth keyboard from your device.
1. Go to Settings > Bluetooth > move the Bluetooth slider to OFF position.

2. Open Notes, Messages or Safari browser and see if the onscreen keyboard appears in any of these apps.
You can remove the Bluetooth keyboard by going Settings > Bluetooth > tap on Info Icon located next to the Bluetooth keyboard > select Forget This Device option on the next screen.
2. Disable One-Handed Keyboard
While “One-handed keyboard” feature on iPhone allows users to type more easily with one hand by shifting the keyboard to one side of the screen, it can sometimes result in the keyboard being pushed to far to the side.
1. Go to Settings > General > Keyboard > One-Handed Keyboard.
2. On the next screen, disable One-Handed keyboard by selecting the OFF option.

After disabling one-handed keyboard, you should find the regular iPhone keyboard being clearly visible and readily available for typing.
3. Disable Reachability Feature
The Reachability feature on iPhone is designed to make devices with larger screens easier to operate with one hand. However, it is also known to cause the on-screen keyboard to fail to appear in certain apps and browsers.
1. Go to Settings > Accessibility > Touch.
2. On the next screen, disable Reachability by moving the toggle to OFF position.

This should prevent the possibility of your iPhone keyboard being hidden by the Reachability feature.
4. Disable Other Keyboards
Disable third-party keyboards on your iPhone and see if this helps in fixing the issue.
1. Go to Settings > General > Keyboard > select the third-party Keyboard.
2. On the next screen, disable the keyboard by moving the slider to OFF position.

After disabling the third-party keyboard, see if the default iOS Keyboard is back and working properly on your device.
5. Reset Keyboard Dictionary
Over a period of time the Keyboard Dictionary can become filled up and sometimes get corrupted.
1. Go to Settings > General > Transfer or Reset iPhone > Reset.
2. On the next screen, select Reset Keyboard Dictionary option.

After clearing Keyboard Dictionary, see if the keyboard becomes available when you use the Notes or the Messages App.
6. Reset All Settings
If above methods did not help, you can Reset all the settings on iPhone to its original Factory Default values and see if this helps in fixing the problem.
1. Go to Settings > General > Transfer or Reset iPhone > select the Reset option.
2. On the pop-up, select Reset All Settings option.

3. Enter Password > Confirm that you do want to Reset All Settings on your device and wait for the Reset process to be completed.
While this step does not erase any data from your device, it removes Wi-Fi Network, Apple Pay and your Location and Privacy Settings. This means, you will be required to rejoin Wi-Fi Network, Add Apple Pay and re-configure your personalized location and privacy settings (If any).