Many phase field fracture models that have been implemented to date are opinionated regarding the choice of elastic model, plastic model, damage model, etc. While this enables easier development of the formulation itself, the resulting model is inflexible and often only applies to a subset of problems of interest. Further, if a change in model is desired, it may be required to redo much of the derivation and implementation. This work aims to develop and implement a generalized, variational, fully-coupled, and modular phase field fracture formulation capable of handling a diverse range of problems. The choices of elastic model, plastic model, damage model, rate-(in)dependence, degradation functions, and tension-compression split are all modularized with well-developed interfaces, enabling the development of solver infrastructure independent from the particular choices of models. While this approach brings its own challenges, it also enables classes of models which were previously tedious to implement, thus allowing the exploration of more complex problems. In this presentation, we detail this modular approach from analytical derivations through to implementation in SIERRA, a robust multi-physical finite element code developed at Sandia National Laboratories. The approach will be demonstrated for several canonical model forms, including elastic and elastic-plastic fracture mechanics. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology \& Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.