Code:
sudo apt update
sudo apt upgrade
sudo apt install bc
sudo rmmod r8188eu.ko
git clone https://github.com/aircrack-ng/rtl8188eus.git
cd rtl8188eus
sudo -i
echo "blacklist r8188eu.ko">"/etc/modprobe.d/realtek.conf"
exit
make
sudo make install
sudo modprobe 8188eu
sudo reboot
So this will install the driver

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To make the interface in the monitor mode after the rebooting:

Code:
sudo rmmod r8188eu.ko
sudo modprobe 8188eu
Now you need to remove and reconnect the USB from the VBox, so in the left up of the window click on (Devices) then click on the USB this will remove it, click again on it so it will reconnect the USB to the VBox

Code:
sudo ip link set wlan0 down
sudo airmon-ng check kill
sudo iw dev wlan0 set type monitor
This will make the interface (wlan0) as a Monitor Mode

To make sure
Code:
sudo iwconfig
This should show you the interface with (Mode:Monitor)

Monitor.jpg