In content examples, “morph targets” map they morphed a cube to a sphere by making a skeleton for cube and animate it,
I don’t know how did they manage to do that since there’s no bones !, also I’d like to know if there’s an easy way to convert my static mesh to a morph target.
nice sir (+1 for particularly good with faces and other stretchy things) that’s exactly what i’m looking for 
another thing, will UE4 automatically create an animation sequence for my morph target after importing or I need to make one by my self ??
These need to be created when the item is modeled in Maya or Max. In a very brief overview, they work by creating two static meshes with the same vertex count. You can then blend between these meshes to say it’s 20% cube and 80% sphere by driving weights in the blueprint.
It’s an alternative to bone animation - particularly good with faces and other stretchy things
Once you have a model set up with morph targets, there’s a tick box to import them on the mesh importer dialog box.
If you have animation keys for your morph targets it should just work (like a bone animation). I made a test morph target for this bug report if you need a sample : Morph targets have very poor performance in game vs editor - Character & Animation - Epic Developer Community Forums
You need to tell the system to change. If you have 100% cube 0% sphere all the time (no change in values), it’s the same as a static mesh.
You can change those values via keyframes or blueprint code. Just like a bone really. If you do neither then it’s never going to change the base mesh. Think of it as another animation parameter.
If I remember right it will be a skeletal mesh - as it’s not static (it moves!).
Also, in case of confusion, fbx and obj are different formats. Fbx will work, obj is simpler and won’t work with anims.
so basically whenever I set a morph target I need to set a key frame for it regardless of animation type (with bones or not ),am I right sir ?
sorry for annoying again,
Sir when blending shapes in Maya and set key frames, then exporting it as fbx obj,will UE4 import it as skeletal mesh or there’s another option for that ??
All credits goes to @MichaelCable ,
To get everything done, here are basic tutorials that helped me out using Maya :
1- Selecting the Joint Tool (Skeleton > Joint Tool) from the Animation menu set,and press once in the middle of your mesh.
2- Open the Outliner (Window > Outliner) and select the joint (by clicking the name), then shift select the mesh (the parent).
3- Parenting step, To connect the two, choose Skin > Bind Skin > Smooth Bind from the Animation menu set.
Remember when you export the fbx to check the blend shapes tick box under deformed model under animation.