Once a pick list exists (see Picking and packing orders with pick lists), this is the picking screen. Picking never changes your inventory - Shopify already holds the units as committed, and the fulfillment does the deduction.
Pick
The list opens in pick mode. Lines are sorted by bin, using the bin locations on each product's stock settings at that location, with lines that have no bin at the end. Switch to By order to walk one order at a time instead.
The next line to pick has a dark bin chip, and the bar under Pick fills as you go. Beside the lines, Orders shows each order in the list with its stage (To pick, Picking, Picked, or how many lines came up short), Details shows the location, who the list is assigned to (Reassign hands it to another staff member), when picking started and how many lines are short, and History keeps the trail. If Shopify changed a quantity after the list was made, the line shows was N beside the new number.
Scan a product's barcode or SKU and the matching line goes up by one. A code that is not on the list, or a line that is already fully picked, plays the miss sound and says why.
Tap the number under Picked to pick one more. A line that is complete taps back to 0 if you need to put it back - the history records it.
Choose Short when the shelf has fewer than needed. Say what happened (not in the bin, damaged, none in stock) and what to do about the rest. Count this bin asks how many units of the item are at the location right now (the dialog starts from Shopify's on-hand count there) and applies a stock adjustment for the difference - a real adjustment, linked from the line, so the count is fixed without leaving the aisle. Order more puts the missing units on a draft purchase order for the item's supplier at that location; shortfalls from other picks join the same draft, and the line links to it. Pick what's there ships what was picked and leaves the rest open on the order. Every short pick is recorded in the list's history. An item Shopify does not track cannot be counted, and a product with no vendor has no supplier to order from - the dialog says so and you can choose another option.
When every line is picked or short, choose Mark picked. The list moves to the bench. Back to picking reopens it if something was missed - nothing has reached Shopify yet.
Picker links let staff without a Shopify login pick from their phone. On a list that is being picked, choose New picker link under Picker links, type the picker's name and send them the link - it is shown only once. The page shows the list's lines in bin order with the order number, product, SKU and picked count, and nothing else: no stock levels, no customer details. They scan with a scanner or the camera, tap +1 or Pick all, and can record a Short pick with a reason (the count and order-more options stay with staff in the admin). Their picks land on the list instantly under their name. Choose Revoke to turn a link off; every link stops working the moment the list leaves picking.
Lot-tracked items (lot tracking on, and Track lots on the product) show which lot to pick on the line: the lot assigned on the order page, or the same first-expiry-first suggestion that page offers. Scanning the batch label picks the line and marks the lot confirmed - on the admin page, on a picker link and in POS. The printed pick list names the lot too. Confirming a lot on a pick list never moves lot balances; that still happens when staff save the lot assignment on the order.
Pickup orders in POS: the Pickup orders tile on the POS home screen lists the pickup orders waiting at that location. Open one, scan every item (or tap +1 / Pick all), and choose Ready for pickup - Stockroom marks the list picked, packs the order and sends Shopify's own ready-for-pickup notification. It is the same pick list the admin page shows, so progress is shared. POS cannot ask for the fulfillment permission itself: grant it once from the Stockroom app (any pick list, Ready for pickup) and the tile works from then on.