I want to know if it is possible to use the keyboard library with the ESP32 but I have not found information regarding that
No, that library is for board with ATmega32u4 or SAMD MCUs.
With ESP32 you could easily implement a BLE HID device, check a tutorial like this for example.
edit:
The library used in the example
But I have problems when connecting the esp32 via Bluetooth and I wanted to see if it was possible to do it via USB. use BLE keyboard library but connection fails
I wanted to use the ESP32 in this case because I don't have Arduino nano
It's possible for sure, but not with the USB port used for flash programming: that port is connected to an USB/TTL converter. You need to emulate a HID device.
After a quick googling, I've found this library which should do what you are looking for.
With this I will be able to use the ESP32 in a USB keyboard? or will it still continue via bluetooth?
The library it's called EspTinyUSB 
Check the readme in the repo and you will find all info needed.
Your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advice on) your project See About the Installation & Troubleshooting category.
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.