The best mutual fund to invest is one that meets your life goals.
Assuming this will be a long journey, you need a mutual fund that has a good reputation, a reasonable and stable Asset base Under Management (AUM), good track record of not falling behind the market too much, and less volatility in returns. Of course the fund manager needs to be a sound professional, backed by strong processes from the fund house.
You can read more on Which Fund Suits You The Best? and How to Select the Best Mutual Fund