There are no charges as such if you invest in direct plan mutual funds. If you do not invest in ‘Direct Plan’ funds you lose upto 40% of your total investment to broker commissions over the long run.
When you invest through one of the Registrar & Transfer Agency (i.e. Karvy, CAMS) you are limited to the funds that they service only. So you may not get access to the best of funds available across the mutual fund industry.Upvote91