What is shipping label?
A shipping label is a printed document that contains information about a package, such as its origin and destination. It’s attached to the package before it’s shipped.
Please go to Sales >> Invoices >> More(three dots besides the desired invoice) >> Shipping label
View the shipping label >> Settings(if any change is required)
Choose as per requirement >> Save and Update.
If you want to add instructions to the shipping label, go to edit invoice >> Notes >> Add notes >> It will be reflected as instructions in shipping label.