After you processed your character, you will be able to use it in external software without restrictions. Read on to learn how to export your character mesh with shape keys.
You can import FBX files into many programs, including GameEngines like Unreal or Unity.
File > Export > FBX (.fbx)
To use the shape keys for Animation and Motion Capture, you do not need the Armature(Rig) generated by Faceit. The FaceitArmature object is only needed for generating the shape keys and does not need to be exported.
FBX export settings for shape keys.
In case your character geometry has a subdivision surface modifier in the stack or similar generative modifiers, you need to uncheck the option Apply Modifiers!
In case you want to export the subdivision levels, you will need to apply the modifier before exporting. This will work with shape keys too.
Apply Modifiers will prevent shape keys from exporting (Enabled by Default).
If you cannot find the export button in the export menu, you will have to enable the FBX Add-on in the preferences first.
Test if your export worked by importing the FBX into Blender right after the export. This narrows down the source of error to the Blender export settings and you don't have to worry about the import settings of your external software. If the mesh has no shape keys or the animation did not export properly, change your export settings and repeat the process.
Export > Import > Export...
If you want to use external 3D packages, you will have to check if it supports shape keys first. Check out the Terminology section for alternative terms for Shape Key.
Unreal Engine 4 Import
To get the import settings in UE4 right, I recommend to read through this article by Epic Games:
FBX Morph Target Pipeline
shape keys are named Morph Targets in the UE environment.
FBX Import Settings - Image by Epic Games from FBX Morph Target Pipeline
To use the exported FBX in Unity, I recommend to read through this article by Epic Games:
Working with blend shapes
shape keys are named blendshapes (or blend shapes) in the Unity environment.