Just like any product or service, even mutual funds charge a small fee for managing your money. This fee is charged in the form of an expense ratio.
If your portfolio requires a smallcap fund, you should consider the NFO as one of your options
Asset Management Companies are required to disclose the TER of all schemes on a daily basis on their websites
The daily NAV of a mutual fund is disclosed after deducting the expenses; bigger funds ideally have lower expense ratio