Your logo, margins, page size and the footer with your bank details apply to every printed invoice, letter and statement. Set them once, then print one invoice to check.

General

Open Settings, then Documents & Printing. Under General, upload the Logo image and set Logo height (your logo will scale to this height while keeping its proportions). Under Business, choose what goes on printed invoices, payments, and account statements: Include business name, address, contact information and registration number, and Include extra information with its text, for bank details, additional contact information, or other print notes. Page size and margins are set on each kind of document; if you print on pre-printed letterhead paper, raise the top margin so the content starts below your printed header and switch the logo off.

The Documents and Printing settings page with a logo preview, logo height and spacing fields, a page size choice, margin fields and sections for Invoices, Letters, Statements, Treatment Notes and Patient Forms.
Documents and Printing with the clinic logo at 60 px, A4 page size and the Invoices section open.

Per document

SectionOptions
InvoicesShow logo, Page size (A4, US letter or A5) and its own Top margin for letterhead.
LettersShow logo, Space underneath logo and the four margins. The practitioner's e-signature, if saved, prints where the letter template places it.
StatementsShow logo and the statement's Title.
Treatment NotesShow logo, Page size, Top margin and Hide unselected checkboxes: remove unchecked boxes when exporting treatment notes to PDF, which makes a long checklist note readable.
Patient FormsThe same options for exported forms.

Document settings updated successfully confirms a save; Last saved shows when. Open any invoice's PDF afterward to check the result. Invoice numbering and payment terms are separate, under Invoice Settings.