Your invoicing profile
The company details every invoice carries, why changing them never rewrites an old invoice, and the fields only e-invoices need.
Settings, Invoicing holds the company details that appear on every invoice you issue.
You can change them any time; a change never alters an invoice you have already issued.
That sentence is the important one. Your details are snapshotted onto each invoice at the moment you issue it. Move offices next year and last year's invoices still show last year's address, which is what they should show.
Company
Legal name, street and number, an optional second address line, postal code, city and country.
The legal name is the name you trade under legally, not your brand. If those differ, this field takes the legal one.
Tax
Your tax number and your VAT ID. The checklist needs at least one of them.
The small business scheme switch (Paragraph 19 UStG) changes what Steerd derives everywhere else: your invoices carry no VAT, and you are permanently exempt from issuing e-invoices. Turn it on only if it actually applies to you.
Bank details
Your IBAN, so clients know where to pay. An e-invoice will not go out without it, because a machine-readable invoice has to say how it can be paid.
Numbering
The prefix and pattern for your invoice numbers, with a live preview of the next number. See Invoice numbers and numbering patterns.
The fields only e-invoices need
A contact name, contact email and contact phone number, plus an electronic address, typically your invoicing email.
These sit unused until you issue an e-invoice, and then all of them are required at once. Filling them in now costs a minute; discovering them at the moment you are trying to issue is worse. See e-Invoicing.
Who can see this
The page follows the invoicing permission. Without it, the screen tells you so rather than sitting on an empty form:
You may not have access to invoicing on this team.