Complex sentence: This is Lovato's sixth headlining tour, promoting her studio album "Confident" (2015); for Jonas, it is his third concert tour, promoting his "self-titled" second studio album and upcoming third album.
Split into simpler sentences: This is Lovato's sixth headlining tour, promoting her studio album "Confident". For Jonas, it is his third concert tour, promoting his "self-titled" second studio album and upcoming third album.