The starting point is the full decision, proof of service, previous applications, earlier decisions and documents on the personal situation. Depending on the topic, medical records, family documents, residence cards, employment confirmations or translations may be added.
A short chronology is important. When was something applied for, served, answered or supplemented? This sequence helps identify open deadlines and possible gaps.
For medical reasons, the file should also show the diagnosis and treatment, required medication, date of the records and the concrete burden created by travel or return. The article on documents for legal review explains how to organise the complete file.