A: Oh, this is to Germany.
How will you send it?+
B: By registered mail.
(What is the meaning of 'this is to Germany'? What is the role of 'to' in this sentence?)
The word "this" must refer to the envelope or package being mailed. The word "to" is a preposition with "Germany" as the object of the preposition.
The sentence seems to mean, "This (package) is (being mailed) to Germany."