To copy bone constraints from one bone to other bones:
- In Blender Preferences > Add-ons:
Find the Interface: Copy Attributes Menu add-on, and enable it.
- In Armature Pose Mode,
Select one or more bones, and select last the bone that has the constraints you want to copy.
- Press Ctrl + C to open the Copy Attributes menu, and select Copy Bone Constraints.
Quickly setup bone constraints