Provident Fund is an account where money is deposited to safeguard your life after retirement. Provident funds are either handled by your employer, government or other institutions.
Provident fund for employees is a fund recognised by government where employees and employer both contribute certain percentage of your salary and this money is tax free.
In India, normally PF is paid at 12% by employees on their basic salary and employer has to pay same amount of contribution.
Provident fund can be withdrawn at any time, however there are tax implications on earlier withdrawal of funds from your PF account.