The process of modifying mesh edges is similar to vertices. Start by setting the selection filter to Edges. After that, select the desired edge(s) to be modified. then you can change the location, the orientation, or the size of the selected mesh edges. Each of these operations can be done using the respective Gizmo tool as shown in the following diagram:

Notice that in all cases, the connected cells are dynamically modified with the changes you make.

Now, let's have a look at the modification of the final element of the mesh cells, which are the faces.