Whether you are running Kali Linux or Nethunter on Android there would be a need that you would want to access your file manager right from your Android.
How to use your file manager in Kali Linux and nethunter
step one
run ls to see what is in your directory
step2 run the below command

sudo nano install-nethunter-termux
After running the above command edit the file according to this tutorial
Run ls again to see what you have in your directory

install-nethunter-termux
kalifs-arm64-full.tar.xz
install-arm64 storage

save then reinstall nethunter following the tutorial below

Follow this tutorial to use your android file manager in linux Tutorial guide
Follow the guide step by step
good luck guys