How do I claim the marriage allowance?
The marriage allowance allows an individual to transfer some of their personal allowance to their spouse or civil partner. This helps to reduce your spouse or partner's tax bill by up to £252.
The marriage allowance is different from the married couples allowance (which should be claimed if one of you is born before 6 April 1935, as it's likely to be more beneficial than the marriage allowance)
If your income is below the threshold, an option will automatically appear in untied as part of the tax return questions when filing your self assessment. Selecting this option and providing some additional information will allow you to transfer the marriage allowance to a spouse or civil partner.
If you are receiving the marriage allowance from your spouse, then there isn't actually anywhere to claim this on the HMRC tax return. Instead, your spouse should transfer this on their tax return, or follow the HMRC guidance here to apply for the transfer.
If the transfer is already in place, this should automatically populate on the tax calculation when submitting your tax return to HMRC.