Type II DFT solutions from Poisson-Lie T-duality/plurality

String theory has the T-duality symmetry when the target space has Abelian isometries. A generalization of the T-duality, where the isometry group is non-Abelian, is known as the non-Abelian T-duality, which works well as a solution-generating technique in supergravity. In this paper, we describe the non-Abelian T-duality as a kind of O(D,D) transformation when the isometry group acts without isotropy. We then provide a duality transformation rule for the Ramond-Ramond fields by using the technique of double field theory (DFT). We also study a more general class of solution-generating technique, the Poisson-Lie (PL) T-duality or T-plurality. We describe the PL T-plurality as an O(n,n) transformation and clearly show the covariance of the DFT equations of motion by using the gauged DFT. We further discuss the PL T-plurality with spectator fields, and study an application to the AdS$_5\times$S$^5$ solution. The dilaton puzzle known in the context of the PL T-plurality is resolved with the help of DFT.