What is the best way to add remarks to changes

Assume a scenario that user need to do some modification to a big data form, while the requirement is that if they have changed some records, they need to add remarks that what have changed,etc.

One solution is to set the remarks part layout beside the main data area, say, right side or below.

As the main data are presented in a table, and user is able to select one record row, do the changes, and add remarks directly.While it is directly operation and user can do the changes and add remarks at the same time. The disadvantage point is that user may not aware of the table row changes also connected to the outside part, and the other way is user may not know if they have changed or not.

The other solution is to give a pop up window to add the remarks, while there is a clear save button to confirm the remarks action, but there is also 2 step more than the first solution, open and close. The other question is the remarks is not easy to view as it need a extra action.

So my question is, for this kind of modification data task, is there some better way to let user can easily add the remarks and clear know what they have done?