Pension in the Netherlands is generally based on three pillars:
the AOW (General Old Age Pensions Act),
the company pension,
and the additional private pension provision.
You build up your AOW through your social security, your company pension will be built up through your employer and your additional private pension can be taken out by yourself via an insurance company.
Please note, not every employer has a company pension scheme. The Dutch tax law has several provisions for savings for the future of which contributions are (partly) tax deductible (and future payments taxable), or tax-free saved amounts (i.e. netto-pensioen/lijfrente).