Purchase blank staff paper, often called music paper. Each sheet of staff paper has between 10 and 12 sets of five lines and four space called music staves (staffs). These staff are where youwrite the notes to your music, just as you would write notes for other instruments. The difference is, you will be adding lyrics to go with the notes.
Mentally group the staffs into groups of three, which is what you will need for a vocal part and a piano part. The vocal line will take the top staff of that group of three and the piano part will take the next two. Then you will start the process again, using as many sheets of staff paper as it takes to complete the song.
Write your lyrics in the empty space below the staff that contains the notes for your words (before the two staffs with the piano music). Place each word or syllable directly under the note the singer will sing for that particular word or syllable. Use hyphens to separate syllables in words.
Ensure as you write the piano part and the notes for the words that the bars of your music match up. Keep the first bar of music for the lyrics lined up with the first bar of the piano part, which will allow anyone reading your song to hear how all the musical parts go together.