Child Tax Credit has been replaced by Universal Credit as the main benefit for anyone with responsibility for a child that usually lives with them.
You can no longer make a new claim for it unless you're claiming Working Tax Credit.
If you need extra support, you will need to make a claim for the child element of Universal Credit. How much you get will depend on your household income. You may also be able to claim the disabled child addition.
Depending on your child’s condition and the support they need, you could get from £128.25 to £402.41 a month (2021/22) as part of your Universal Credit payment.
If you're already getting Child Tax Credit and your child develops a disability or long-term health condition, you might able to claim an extra disabled premium for them.
Depending your child’s condition and the support they need, you could get between £3,435 and £4,825 a year (2021/22) as part of your Child Tax Credit payment.