How do you save your bank details on invoice so you don't have to keep adding them all the time

Yes, you can add your bank details to your invoice template in QuickBooks Online by customising the footer in Custom form styles.

Here's how:

1. Go to the Settings icon and choose Custom form styles.
2. Locate the Standard style or your invoice template and click Edit from the Action column.
3. On the Content page, choose the pencil in the bottom-right corner to edit the footer section.
4. In the Add payment details and footer section, add your bank details to the footer.
5. Select Preview PDF to review the changes before saving.
6. Click Done.

Note: The changes will apply only to newly created invoices after the invoice customisation has been applied.

For more details, click this article: Adding bank details to your invoices.

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