When you are writing for voice that includes lyrics, slurs are usually used only when there is a melisma: 2 or more notes assigned to the same lyric. Slurs in instrumental parts are used to indicate phrasing. However, in vocal music, the text is the phrasing.
For more information on entering slurs, see my other blog posts:
Both Finale and Sibelius include plug-ins that will automatically apply slurs to melismas so long as they are properly entered in the score.
Sibelius Plug-in: Add Slurs to Lyrics
After entering the notation and lyrics, run the plug-in. The plug-in only applies to lyrics entered in Lyrics Voice 1.
Select a portion or the entire score.
- Choose Text > Plug-ins > Text > Add Slurs to Lyrics
After running the plug-in, two slurs were added:
Finale Plug-in: Auto Slur Melismas
Enter the notation and the lyrics.
- Choose Plug-ins > Lyrics > Auto Slur Melismas