Comments allow you to place text on the screen without actually placing a field. You can use a text symbol or a field name. Field name has to be a maximum length of 8 characters. Character field must not be declared with DATA statement, but is declared automatically when you declare length of your comment.
* SELECTION-SCREEN COMMENT /startingPosition(Length)
SELECTION-SCREEN ULINE /40(8).
SELECTION-SCREEN COMMENT /40(15) text-001.
SELECTION-SCREEN COMMENT /40(15) comm1.
SELECTION-SCREEN SKIP 2. " put number of lines to skip after SKIP statement
INITIALIZATION.
comm1 = 'Hello SAP'.