Marriage Allowance is a beneficial tax relief for married couples and civil partners in the UK. It allows a lower-earning spouse to transfer a portion of their Personal Allowance to their higher-earning partner, potentially reducing the tax they pay. This article elucidates the process of applying for the Marriage Allowance, ensuring that eligible couples can take advantage of this tax relief. How to Apply for Marriage Allowance in the UK (2025-26) | Complete Guide by Pro Tax