Extend the working admin panel for buy, sell and repair webste

We're looking for a developer that can extend our working admin panel. We want to be able to print automatically generated receipts, qr labels, stock control. Buying system (add transaction to the system, add bought item to the stock, generate receipt of sale) Selling system (add stock to database option, generate and print qr code for each item, print invoice) Repairing system ( book item for the repair, generate receipt for client that item has been left for the repair, once repair marked as completed generate invoice in pdf)