What a dividend voucher is
A dividend voucher is the record of one dividend paid to one shareholder. It shows the company, the shareholder, how many shares they hold, the amount per share, the date it was paid and the total they received. The shareholder keeps it as their record for their tax return, and the company keeps a copy with its books.
GOV.UK says that for each dividend payment, the company must write up a voucher, give a copy to the shareholder and keep a copy. That's true even if you're the only director and the only shareholder. See taking money out of a limited company.
Dividends can only come from profit. A company can only pay a dividend if it has enough retained profit to cover it. That's broadly its profits after tax from this year and earlier years, less any losses and dividends already paid. Check before you pay. A dividend paid without enough profit can be unlawful, and the shareholder may have to pay it back.
The board minute
Before the company pays a dividend, the directors hold a meeting to declare it, and keep minutes, even if there is only one director. An interim dividend is usually declared by the directors. A final dividend is usually recommended by the directors and approved by the shareholders. Your company's articles of association set the rules, so check them. The minute this tool writes is a simple starting point.
No tax credit
Older vouchers showed a "tax credit". It was abolished from 6 April 2016, so a voucher for a dividend paid now shouldn't show one. This tool doesn't.
This tool helps you lay out vouchers and minutes. It isn't legal or tax advice. Shareholders may owe Income Tax on dividends over the dividend allowance. Rates and the allowance can change, so check tax on dividends on GOV.UK.