What action should be taken after entering a unique network key for invoicing?

After entering a unique network key for invoicing, the appropriate action is to click Save to finalize the entry. This step is crucial because saving ensures that the entered network key is stored correctly in the system, allowing for proper invoicing processes and ensuring that any associated transactions can be completed without issues.

Finalizing the entry by saving it also prevents the loss of data that may occur if the user were to navigate away from the page or close the application without saving. It's essential for maintaining accuracy and integrity in financial records, which is a core principle in accounting practices within Xero.

The other options would not contribute positively to the workflow. Deleting the network key or ignoring it could lead to complications in invoice processing, while logging out of Xero immediately would mean losing the changes made and complicating future entries or tasks. Therefore, clicking Save is the logical and necessary step to make sure the network key is preserved and utilized correctly for invoicing purposes.