what is the procedure for obtaining a verpflichtungserklärung(formal obligation letter) and are the documents required to submitted bz the host at the Ausländerbehörde? i need a verpflichtungserklärung(formal obligation letter) instead of the blocked account for the proof of my financial means to apply for a long term student visa from India. Please let me know the maximum validity possible for the same.

Verpflichtungerklärung will be issued by the Ausländerbehörde of your Sponsor !

Though the prerequisite is either Verpflichtungserklärung or Sperrkonto für the duration of your Study period multiplied by 720 EUR per month, recently I experienced that Ausländerbehorde asked me furnish Sperrkonto as well for my Invitee before issuance of Visa. So I suggest you to prepare both, as otherwise your Visa Application might get stuck last minute.

hello,
 
can a close german friend issue me a Verpflichtungserklärung to join them in Germany? and how long can it be for? and does it always work

thank you