We don’t do manual vertices changes here (at least to my knowledge). That is something which you can do with a 3D modeling software.
Now that being said, you can do the same style of change, how you do it depends on what you are trying to do.
You can select a face and make changes to it like a sketch. So push pull twist, or if you select a vertices you can chamfer or filet.
Your other option is to manipulate the base sketches vertices or take your vertices and make a sketch on it to make a series of operations to get a similar change.
The reason being, in CAD, you can undo or change underneath and if you can it by vertices, which one did you select if you go back and add a new face? FreeCAD specifically has a hard time keeping track of which vertices is which on a recompute.
The other thing unlike modeling CAD is all about measurements, so making sure that the change is anchored and can handle an entire model change is part of the good cad design. For example if you need to pad out a width in step 2, and in step 30 you modify your vertices, but after a print you realize that you padded to much in step 2, your design should be able to handle changing the pad and not breaking at step 30. (Note this is not easy to do in FreeCAD without practice)
Here are a few of my designs if you need a reference of a workflow: https://github.com/the16bitgamer/16BitVirtualStudiosDesigns