You can normally take a retirement lump sum tax free, although the actual amount you can take depends on the type of pension arrangement. You can then usually use the rest of your fund to buy an annuity (a pension) or invest it in an Approved Retirement Fund (ARF), in order to provide you with an income in retirement.
Prior to your retirement you should receive detailed information to your actual options. You should carefully study these options before you make a decision.