I have found my mother's information here, and it's showing an incorrect date of her death. It says 1977 when she in face passed away in 1997. The photo clearly shows on the headstone 1997. How can this be rectified?
It is a common misconception that the page you were viewing (showing incorrect details for the death of your mother, in this case) can be seen by others. However, nobody knows to what you are referring. If you can explain the nature of the record (FamilySearch or Find A Grave, perhaps) you will be provided with the appropriate advice.
You are able to correct the death date in your mother's record yourself. Here is what you can do: