Exact documents depend on your program, but common items include transcripts/degree certificates, CV, motivation letter/statement of purpose, and language certificates (English or German depending on the program), plus any country-specific verification requirements.
In recipient stories, research-focused applications were document-heavy: Kirti Patil said she attached “my CV, academic transcripts, and a brief research proposal,” and she also highlighted needing a formal invitation letter from a professor as a critical requirement for her scholarship application.
Subhadip Saha similarly pointed to a strong proposal plus a “Letter of Motivation/Cover Letter,” an “eye-catching CV,” and a strong recommendation from his supervisor.