The comments field is a field used to store historical record of User comments and an audit of the items edits/history.
Visit the Forms tab to access the Field List and Default formModules (top left) → Module Name → Forms (tab)
Ensure the Comment field is not marked ‘Hide in form’ first in the Field List.
Once verified in the Field List, the field has to also be added to the Default form.
Drag the Comment form field from the palette on the right to the form layout on the left.
Preview the form and ensure the form field is present.
Save the Default form and verify the field is on the form when editing/creating requests from the grid.
If you have double checked the above points and the field is still not visible, please contact Stratawise Support