If your personal details change, you may be required to notify HMRC as this can affect your entitlement to certain tax breaks and or benefits.
For example, you need to tell HMRC if:
You can tell HMRC online if you are paid a salary or pension through PAYE. The sooner you tell HMRC the better as the change could result in you paying too much or too little tax.
If you receive tax credits or Child Benefit you also need to tell HMRC separately about changes to your relationship or family.
In the event, that your spouse or civil partner dies it is also a requirement to report the death to HMRC as well as notifying of changes to your income. For example, the death of a spouse would mean that the surviving spouse was no longer entitled to claim the Married Couple's Allowance.
If you move home, it is of course advisable to let HMRC know as soon as possible so they can update your contact details. HMRC should also be informed if you change gender, although the process is usually automatic if you apply for a Gender Recognition Certificate.