Decision from the Ausländerbehörde (immigration office)
A Bescheid is a letter in which an office decides something about your case.
Not for letters from the BAMF: their deadlines are much shorter, often one or two weeks. If the letter says you must leave Germany, get advice right away.
What you can do
The Rechtsbehelfsbelehrung is a text at the end of a Bescheid. It explains how you can challenge the decision.
Read the Rechtsbehelfsbelehrung first. Write down the deadline and where your answer has to go.
Get advice before you file a Klage, for example at an advice centre or a law firm. Do not wait until just before the deadline ends.
If you do nothing, the Bescheid usually becomes final when the deadline ends.