Your baby's birth must be registered in the district where the baby was born, this can be done in your local registration office or you may be able to register the birth in hospital before the mother goes home.
If it is not convenient for you to visit your local registration office for the district, you can go to any other registration office in England and Wales (within 42 days of your baby's date of birth) to make a declaration of the particulars required for the registration. In that case, any birth certificates you require will be sent to you by post.
Please remember that you have a legal duty to register the birth within 42 days.