If you would like to authorize someone to collect your passport on your behalf, here is a sample template you can use to write a passport authorization letter.
Subject: Passport Authorization
To Whomsoever It May Concern
I, (Your Name), the undersigned, hereby authorize (Authorized Name) to collect the passport on my behalf from (Location). As I am unable to collect the passport due to personal reasons, I give my consent to (Authorized Name) to collect the passport from your office. I request passport authorization.
The details of my Passport are provided below.
Name on the Passport:
Let me know if you have any questions.