This depends on the scope within your pension scheme. On the home page of your personal pension page, you can see whether you can invest an extra amount every month under ‘Planner and extra pension’. You can state here how much additional pension contribution you want to pay in each month. Your employer will then withhold the additional pension contribution from your salary and pay this contribution to BeFrank.
You can use the ‘Pension planner’ to perform a calculation to see what it means for your pension if you pay in additional pension.