The oath and the final stage: when the status actually begins

An approval letter is not a citizenship. In most systems the status begins at a defined moment afterwards, and a number of things then have to happen in a particular order.

The final steps

• The decision — approval, notified in writing.
• An oath or declaration, in many countries at a public ceremony. In several systems, including the United Kingdom and the United States, citizenship legally begins at the ceremony rather than at the approval, and there is a deadline to attend one.
• Registration in the civil register, which in continental systems is the constitutive act.
• Issue of an identity document and a passport, applied for separately after the status exists.

What has to be done afterwards, and often is not

• Notify your existing country of citizenship where it requires it. Several countries impose a duty to declare a second nationality within a defined period, with penalties for silence.
• Establish whether you have lost the previous citizenship automatically. A number of countries provide for automatic loss on voluntary acquisition of another, and the person concerned is frequently the last to know.
• Decide which passport you travel on where. Some countries require their citizens to enter and leave on their own document, and travelling on the other one is an offence.
• Update tax filings and bank self-certifications, because your citizenship is a reported field.
• Consider military obligations that attach on naturalisation, for you or for children.
• Register children where they derive citizenship from your acquisition — it is rarely automatic and often has a window.

The document to keep permanently

The naturalisation certificate or the register extract. Passports expire and are replaced; the document proving how and when you became a citizen is the one every subsequent authority will ask for, sometimes decades later, and reissuing it is a procedure. Keep the original somewhere safe and a scan somewhere reachable.