How much can I withdraw from my investments ?

There are no set rules and you can withdraw periodically unless there is a lock-in-period. You can withdraw a lump sum amount or as and when required. However, you should withdraw only if you need money for an emergency or for a specific goal. If you make a profit, you can reinvest the money but before you do, take into consideration the fees and taxes you will be paying for every time you do this.