Hi NoNameGodLike,
We do have a geometry editing system inside of UE4 but it is intended for blocking out your level and should be replaced with custom meshes created in 3d modeling software.
Take a look at the link below for more info on the correct pipeline to create assets for UE4.
Another tutorial that goes through the process step by step.
http://www.digitaltutors.com/tutorial/1635-Game-Asset-Production-Pipeline-in-Unreal-Engine
TJ