Request tax ID
Tax ID not received after moving to Germany — what now?
After first registration in Germany the Bundeszentralamt für Steuern issues the number of its own accord. It arrives by post; you do not have to apply for it.
This usually takes up to three months. As long as that period has not passed, asking speeds nothing up; it is worth waiting.
If nothing has arrived after more than three months, ask in writing. You then need the Meldebestätigung (confirmation of registration) and a copy of an identity document.
Why it takes so long at all
The number is not created at the registration itself. The registration office transmits your data to the Bundeszentralamt, the number is issued there and sent from there. Several weeks lie between the two steps.
The identity document copy is the exception here
Anyone requesting a number that has already been sent to them does not need to enclose a copy of an identity document. After first registration they do: because no letter has ever gone to you, the office must be able to verify your identity another way. A plain copy is enough, and it is not returned.
The application works without the number too
If you need the number for an application — Kindergeld, Kinderzuschlag, Elterngeld — do not wait for it. What counts is the day the application reaches the office. You submit it without the number and supply it later.
What that costs
The price is fixed. A request always concerns exactly one person, and the letter is always one sheet — there is nothing the extent could depend on. The sample calculations are on the page about Request tax ID.