Today - April 6 - is the start of the new tax year. The financial year runs from April 6 to April 5 and the beginning is usually the day when changes come in.
In previous years this has been with things like the amount you can earn before you pay tax changing, for example, which was welcome news as it meant most people paying less tax. However, the income tax and National Insurance thresholds have been frozen until 2028, meaning there is no such boon this year.
That means the personal allowance is stuck at £12,570 for the foreseeable future. This is the amount everyone can earn before they start to pay tax - i.e. tax is only paid on amounts earned above this figure. This applies in England, Wales and Northern Ireland, Scotland has its own system.