I have these two objects A and B. I want A to follow B but only A's location not rotation.
Everytime I use the parenting method, child object always follows every detail with parent object.
This A object rotates but I want B not to rotate, just follow A's location. How is it possible? Should I use other method? not parenting one?
Blender has a copy location, rotation and scale constraint, as well as a copy transform constraint (ie copy all three_) Adding all of location, rotation and scale, or copy transform with influence 1 and using world space is the equivalent of parenting.
For question example consider adding just a copy location constraint on A targeting B
Example default Cube at location of default Camera. With offset unchecked is at exact global location. With it checked will behave similarly to a child, and be offset from parent based on its location
Leaving above the same: If we add another copy location constraint, targeting the Light, with influence 1, the cube will be at location of Light. With influence 0.5 will be half way between Camera and Light.
For fully controllable parenting, you can use the Child Of constraint, which allows you to select which transforms, and which axes of those transforms, the constrained child object inherits from the target parent object.
You can also use the Influence value of the constraint to hand the child from one parent to another.
Drivers are a form of parenting selected properties (location, rotation, scale) with one variable controlling just one property. In your case you add drivers to location.
Drivers also allow more control, with expressions, than simple constraints. See an example
