Unfortunately, copyright and legal issues with publishers and copyright holders restrict us from including melody and lyrics. 

iReal Pro supports transposable chord charts with play along function.

 

Use split screen on iPads and Android tablets (might not be available in very older devices.)

You can read PDF music charts while using iReal Pro.

For example Mobilesheets (iOS, forScore or similar) to view your text, lyrics, melody notation.

iReal Pro can run in the background.

Alternatively share (export) the audio from your individual songs from iReal Pro, import them and attach to your PDF songs ready to trigger play in that app.

 

You can export any song in music XML format, open it in a music notation software (e.g. Sibelius, Dorico, MuseScore) and then add melody/lyrics as you need to.