The TMD factorization at the next-to-leading power has an involved structure of singularities.
I discuss the definition and properties of transverse momentum dependent (TMD) distributions of the twist-three including evolution,
symmetry relations, parametrization, interpretation, and singularities.
I demonstrate that the physical TMD distributions (in terms of which observables are written) require an extra subtraction procedure.
As an example of application, I discuss the Drell-Yan/SIDIS processes at the next-to-leading power in terms of physical distributions
and explicitly demonstrate the cancellation of rapidity and end-point divergences.
These results complete the construction of TMD factorization at the next-to-leading power.