In Teamleader, invoices and credit notes are generated based on the same template. To access this template, you navigate to Settings > Document layout > Invoices. Click here for more information how to create templates according to your own house style.
You can choose to only display custom fields on an invoice, a credit note, or both. To do so, you simply add the shortcode for that particular custom field to your template (as you usually do), but you'll also need to define to which template the custom field should be added.
To this end, you can use the following shortcodes:
Custom field on invoice and credit note:
Custom field on invoice only:
$CUSTOM_FIELD_1234$ or $CUSTOM_FIELD_1234[INVOICE]$
Custom field on creditnote only:
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