Use DO Shipping Label Print (12.19.17) to create labels for DO shipments. Once you specify the ship-from and container ID, the system automatically fills in the label number, starting at number 1.

You must specify a shipping label template in DO Container/Shipper Control (12.19.24) before you print labels. In the control file, specify either a mixed load, master load, or single load label template. The templates specify the required format for barcode labels that enable shipments to be received with barcode readers.

See here.