Adobe Lightroom synchronization option

As you are using Lightroom 5.5, you can copy all the edit settings from a specific image (or you can choose which edit settings to copy), then you can paste those copied settings to one or many selected images. 

Select the image you want to copy settings from, then click on the tri-dot icon underneath the edit tools on right-side of the edit panel. There you will see the available options (and the respective keyboard shortcuts). i.e.:

Cmd+C to copy all edit settings

Shift+Cmd+C to select which edit settings to copy

Cmd+V to paste the copied edit settings to a single image

Shift+Cmd+V to paste the copied settings to multiple selected images.

Which Lightroom application are you referring to?

Lightroom Classic v 11.5 logo LrC or

Lightroom (cloud-based) v 5.5 logo Lr.