Before you can start to train your voice to sing higher, you must determine your natural range. All the singing you’ll ever do is within your natural range, the interval from your lowest to highest note. The goal in improving your vocal range is to ‘unlock’ the outermost notes of your natural range and be able to sing them comfortably, clearly and beautifully.
To find your vocal range, start at middle C on the keyboard. Middle C is represented as C4 on your sheet music, 4 signifying the 4th octave. Sing each semitone down until you cannot comfortably and clearly hit the notes, this is your lowest note. Then work your way up the keyboard from middle C, singing along with each semitone to find your uppermost note.