If the creditor doesn't show in the list of creditors, it may be a new creditor, which has not yet been added to Spend Cloud. Check whether the creditor appears via Application management> General> Relations. If the creditor does not appear in this overview, the creditor must still be added.
Depending on your settings, you will find a plus icon behind the creditor field. If this is not the case, then you either do not have the correct rights or the creditor must be registered in the financial package. When adding a creditor in the financial package, you can then export the complete creditor list and import it back into the Spend Cloud under the Relations menu item (if this is not done via an automatic import).
In a rights set you can add rights to create creditors when coding an invoice. To do this, check the option "Unknown creditors" in the rights for encoding invoices. Rights to create and assess creditors from the relationship overview can be ticked under "Relations" in Application management> General.
Multiple administrations
Depending on your settings, separate creditor lists may be used per administration. This means that when coding, the creditor list is filtered on the basis of the administration under which the invoice falls. The creditor may not yet have been added for that specific administration. Here too, you can add this with the plus icon behind the field, or you must first add the missing creditor with associated administration to the financial package and then export and import it into the Spend Cloud.