For answers to the most common questions about the procedure, please refer to “Important information for scholarship applicants”:
https://www.daad.de/en/study-and-research-in-germany/scholarships/important-information-for-scholarship-applicants/

A recent TOEFL iBT 79 or IELTS 6.5 test result is mandatory (not older than 2 years by the time of application). One recent reference from a university teacher (with date, handwritten signature, letterhead and stamp of the university), must be delivered in a sealed envelope to our office in Jerusalem by the deadline, it is recommended to use an express mail service such as Aramex or FedEx.