This section of the PDF invoice is extracted from the supplier's company details section, if the site is connected to a depot, then it will use the depots details including the depot title name.
This information can only be edited by the supplier in the supplier portal via the below steps:
Click into Administration on the left panel.
Click into Manage Depots.
Edit the depot.
Update the Title and any other Address Details.
Click Save Changes at the bottom.