Usually it does not work at all - until you enable it.
You need to select bidirectional.
Either
- with the virtual machine running
- windowed
- not full screen
- click on Devices menu
- Shared Clipboard
- Bidirectional
Or
- before starting it
- rightclick on the vm
- Settings
- General
- Advanced tab
- Shared Clipboard
- Bidirectional
As I assume - from your inxi sysinfo - your host is Manjaro - add your host username to vboxusers grup
sudo gpasswd -a $USER vboxusers
If you don’t have the guest iso - sync it from the repo
sudo pacman -Syu virtualbox-guest-iso
Assuming your guest is Windows - you need to insert guest additions from the Devices menu - then install from the image inserted.
If you guest is Manjaro - inside the running guest - add your guest username to vbboxsf group - restart the vm.
If your guest is anything but an Arch Linux based system - insert the guest iso and run the installer.