Two-dimensional (2D) materials and their heterostructures offer unique properties and potential applications compared to traditional bulk materials, due to their ability to deform in both in-plane and out-of-plane directions. Here, I will present the development of new techniques based on nanobeam four-dimensional scanning transmission electron microscopy (4D-STEM) to probe the in-plane strain and out-of-plane structure of 2D materials. The focus will be on 2D monolayer lateral heterojunctions and vdW ferroelectrics, providing valuable structural insights into engineering their electronic properties and ferroelectric domain walls.