Sing Harmonies

This harmony singing app comes with three songs, with 50 more available through in-app purchase. Learn how to sing harmony and polish your harmonizing skills by playing or muting any of the singers as you sing along with 4-part vocal arrangements of "Lean On Me", "Teach Your Children", and "Proud Mary". Harmonizing is easy with this multi-track learning app.

"Great for vocalists who have difficulty hearing or singing harmonies."

https://makingmusicmag.com/8-spectacular-apps-for-singers/

The 50 additional songs available through in-app purchase include "Hallelujah", "Amazing Grace", “Sound of Silence”, “Take Me Home, Country Roads”, "Shallow", "Seven Bridges Road”, “Let it Be”, and many more. Detailed song info is at https://singharmonies.com/.

"One of the best iPad apps for singers.”

https://www.apppicker.com/applists/2488/the-best-ipad-apps-for-singers