Hello see the sample below:
-We sent photocopies of the original consent letter to the USCIS.
-At the NVC stage, we also sent copies and we took the original consent letter to the NVC interview (they asked for it).
-All pages must be notarized, signed and stamped by notary/lawyer.
===
Date
Name of person giving consent
Address
To: U.S. Citizenship and Immigration Services (USCIS) and National Visa Center (NVC)
Re: Application to obtain lawful permanent resident status in the United States of America for (Child Name).
I, (name of person giving consent), biological mother of (child name, DOB), hereby give my written consent for my child to permanently immigrate to the United States of America as a permanent resident to live with his biological father (father name, DOB) and stepmother (stepmother name, DOB).
I also give my consent for (child name) to travel outside of the United States at any given time with either or both his biological father, (father name) and his stepmother (stepmother name).
This letter of consent is valid until (child name) reaches the age of majority of 18 years old.
On page 2 you will find a photocopy of my (passport or drivers license of the person giving consent).
If you have any further questions you contact me at (phone number of the person giving consent).
Signed on this XXth day of (Month, Year) in (City, State, Country)
__________________________________
(Signature of person giving consent)
===