Neither side will hold a tracking number
Both platforms lack the field, so the workflow has to account for it from day one.
Square has no field for a tracking number, and neither does Amazon. So when you post an order from this stock, the number lives in QuickSync and there is no second place to read it from. Nothing is lost. But if your process is for someone to open Amazon or the Square dashboard and read tracking off the record, that process is the thing to change before you connect rather than after.
The upside on this pair is speed. Both Square and Amazon push their changes to us as they happen, so neither is sitting behind a scheduled check. A sale at the till and a sale on Amazon each reach the other side without waiting to be noticed, which is the situation that otherwise produces an oversell on a busy Saturday with a queue at the counter.