Adding to the paradigms that emerge in answers to your other question about what postmodernism is, admitting with others that this is complicated, a simple attempt with few words of my own are: breaking modernism's strict rules, return if wanted to baroque or gothic or other periods, inclusion of humanistic themes, an emphasis upon urbanism, solutions for mankind living in the city, some also returning to nature, of course the modern concern of sustainability (all 17 UN SDGs), embracing of technology for new forms yet some returning almost to a new Arts and Crafts type of movement, fragmentation, deconstruction, minimalism even, all jumbled up.
There are many paradigms of ''Post-Modern'' Architecture, for example: phenomenology, linguistic theory, semiotics, structuralism, post-structuralism, deconstructivism, and feminism.