pop up keyboard lost when I installed IOS 13 on Ipad

Hello,

Unfortunately if that did not resolve your problem then you will need to fully restore your iPad.

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

Hello,

Try resetting iPad's settings in Settings > General > Reset > Reset All Settings. Be certain you do not select Erase All Content and Settings as this will erase all of your information. It is a good idea to perform a backup of your iPad prior to resetting its settings.