This table shows if you have started investing 1000 rupees every month, how much impact it can have basis the interest rate/returns you can generate over years.

Second importatnt parameter is Frequency of interest payment. If you getting returns which is quarterly compounding that means; every quarter interest paid on your deposits and it is added in your total deposit amount. So next quaarter; you earn additional inteerest rate on previously earned interet also thus increasing overall returns for you.

Banks generally pay intrest which is quarterly compounding however PPF generally pays interest which is annual compounding. For mutual funds, there are varrious options available for your choice.

If you are getting 6% returns with annual frequency compared to 6% returns with compounding frequency than both are different. Check how varying compounding frequency can change your returns.