With a defined contribution pension, the first 25% is usually tax free. Beyond that, there are four main options:
Full lump sum
Withdraw the whole pot at once. A quarter is tax free, but the rest is taxed as income, which can push you into a higher tax bracket. For example, from a £100,000 pot, £25,000 would be tax free, but the remaining £75,000 would be added to your income for the year.
Smaller lump sums (UFPLS)
Take ad-hoc withdrawals directly from your untouched pot. Each time, 25% of the withdrawal is tax free and the rest is taxed as income. There is no separate drawdown account and usually no upfront 25% on the whole pot.
Annuity
Use your pot to buy a guaranteed income for life from an insurance company. The advantage is certainty, but the downside is less flexibility and limited inflation protection.
Drawdown
Move some or all of your pension into a flexible retirement income arrangement, often called a drawdown account. You can usually take 25% tax free at the start, while the rest stays invested. You decide how much to take and when, but you take on investment risk and ongoing charges.