Paying into your Penfold through personal contributions means that you pay from your own personal bank account, after you've received your monthly wage in which you have paid tax on. Because you have paid tax on this pension contribution, the government will pay you back the tax you have paid with a 25% tax top up contribution, as a way to incentivise people paying into a personal pension.
Comparatively, you can pay into your pension by making business contributions through your limited company (not a sole trader business). Paying into your pension this way means that these business/ employer contributions will be offset as a business expense and therefore are not susceptible to corporation tax. Therefore, less corporation tax will be deducted from your total company's earnings (dividends). Because you have not paid corporation tax on these business contributions, your contributions will not receive the government's 25% tax top up contribution.
Just note, paying into your pension either way is a really great option - and neither is better than the other, it is just a case of what you think is more beneficial for you and your own financial situation. If you would like some advise on which one to choose, you may want to reach out to a financial adviser to pick the best option for you.