Many traditional freeform games make use of item cards. If you need to track such things in your game then you will need to organise a system to do it.
One option is the use of a shared Google Document that lists all the items in each location. Players can move items between locations and their character sheets by copy/pasting. This would mean that the contents of every location would be visible to all players (as would the contents of their pockets if you make what characters public in the same way) so players would have to keep in and out of character knowledge separate.
You might instead use the announcements channel to notify people of the location of items, which means fewer windows for players to juggle.