How can I invest Rs. 100000 in a fund and systematically transfer Rs. 2500 per month in equity fund for 30 years

Yes, this is quite possible. You can invest Rs. 100,000 in a liquid fund and transfer Rs. 2,500 per month to an equity fund of the same AMC. For example, if you are investing in a liquid fund of ICICI Prudential Mutual Fund then you will have to select an equity fund from ICICI Prudential Mutual Fund only to transfer systematically every month.

We have answered to a similar query recently which provides a detailed reply with example of fund names. You will find it relevant https://www.advisorkhoj.com/post-your-queries/I-have-around-1-crore-to-invest-and-need-a-plan-to-invest-in-the-market-through-SIP-mode

For investing in Direct mode of mutual funds, please visit website of the AMC in whose scheme you have decided to invest and select the direct mode option.