Which documents will the German tax office ask for, and does it depend on my company?

The list depends on the tax office responsible for your country and on your company type, and we ask for all of it once, right after payment. The usual set:

• an extract from your company register
• the articles of association: if they are not in German, German is the safe language for a translation and a plain one is normally enough; the tax office (Finanzamt) may ask for a certified translation (beglaubigte Übersetzung) in justified cases, and we check what your office needs
• the passport of every director (a driving licence is refused)
• every shareholder to 100 percent, with date of birth and home address, and the share capital
• proof of the registered office (for a virtual office, the provider's confirmation)
• a bank proof
• the warehouse or marketplace contract (for Amazon FBA, the seller name and token)
• the real start date of your German activity
• if your company has no VAT number at home, a tax-residency certificate from your home tax authority (for a US company, IRS Form 6166 helps if you have it but is not required)

Documents in Cyrillic or another non-Latin script need a translation too; a plain one is normally enough. Scans are normally enough, so you do not need to post originals, and an apostille is needed only if the Finanzamt explicitly asks for one. If you genuinely do not have an item, say so with one line why; the office accepts that, and the missing item holds the submission, not your account.