If you notice the Manjaro update will include VirtualBox, you should shutdown (or savestate) your guests.
After installing Updates from Manjaro repositories your VirtualBox will be up to date.
After that update, You should usually reboot so that the Virtualbox driver modules that are in memory get replaced, or any kernel updated are applied.
Then open Virtualbox Manager and check for updates. It won’t find any updates to Virtualbox, because that will be up to date already.
But that check will also force a check for updated Oracle VM VirtualBox Extension Pack. The Extension Pack provides drivers for USB and a few other things. They are not absolutely essential, but some USB features don’t work without them. Check the manual link above for details.
Extensions are NOT included in Manjaro Packages for license reasons. You can get them from AUR, but the AUR version don’t always update in sync with the versions of VirtualBox.
That’s why I always fetch them directly from inside VirtualBox Manager via a check-for-update, it always fetches the correct versions.
You can check which versions of the extensions are installed via File / Preferences / Extensions in the Vbox Manager.