How Move Existing Inventory Into Bins
If I enable bins on an account that has been managing inventory without bins for a long time, after I’ve set up the bins and added them to the item records, how do I move the inventory into the different bins? Do I need to use a specific transaction type?
There has to be a starting reference point for your inventory (i.e. Opening Balance) which can be achieved via a Journal Entry.
I agree with @abbott that you may then use the “Adjust Inventory” or “Transfer Inventory” transaction.
You can even move inventory from the Item record itself.
As for new inventory coming from purchases, the transaction would basically be “Purchase Order”.