Incorporation with a shareholder abroad is possible. There are two alternatives:
Alternative 1:
You have the deed notarized by a notary abroad. For this notary, you also need a so-called apostille on the document. This is a confirmation by an authority that the notary is actually licensed. This possibility exists in most countries.
You can find an overview here: https://www.dnoti.de
Alternative 2:
Alternatively, notarizations and certifications by German missions abroad (= embassy) are also possible.
You can find more information at https://www.auswaertiges-amt.de/de/.
We will gladly help you to prepare the appropriate documents and powers of attorney for a notarization abroad.