u/Many-Gain-3848

Hey all, could you please help me with this requirement (Self-addressed envelope of C-5 size, with Euros 4.50 stamp). How exactly this could be done? I was at a DHL shop today to check the same and they suggested to go with 'Einschreiben Rückschein' which is 4.85 Eur.
Please suggest what to do (all the documents are in place, just need to send this out)

Also, can I just drop my envelope (once everything is done) at Indisches General Konsulat Widenmayerstraße 15, 80538 München or should it only be sent by post?