  The general parametrization for spacetimes of spherically symmetric
Lorentzian, traversable wormholes in an arbitrary metric theory of gravity is
presented. The parametrization is similar in spirit to the post-Newtonian
parametrized formalism, but with validity that extends beyond the weak field
region and covers the whole space. Our method is based on a continued-fraction
expansion in terms of a compactified radial coordinate. Calculations of shadows
and quasinormal modes for various examples of parametrization of known wormhole
metrics that we have performed show that, for most cases, the parametrization
provides excellent accuracy already at the first order. Therefore, only a few
parameters are dominant and important for finding potentially observable
quantities in a wormhole background. We have also extended the analysis to the
regime of slow rotation.
