When setting up a skeleton in the HumanIK window, you can export a template of the joint positioning, then re-use that template to build other similar skeletons.
To export a HumanIK skeleton template file
The global translation data for the joints is saved as a text file in the location you selected in the Export Template window.
To import a HumanIK skeleton template file
By default, the character controls templates are created in CharacterControls directory during installation. These files are used to create the default layouts for the Controls and Custom Rig tabs.
The skeleton that you created or loaded updates to use the joint positions from the template file.