How to get Google maps as a background map in ArcMap ?
You could use open web maps.
You could also try Arc2Earth.
Can I use in ArcGIS Desktop 10.3
No. This add-in is not compatible with ArcGIS 10.3 for Desktop, as yet.
You could check if the update of Arc2Earth trial is compatible with v.10.3 or not.
fwiw, Arc2Earth is compatible with ArcGIS 10.3 and will soon be available in ArcGIS Pro as well
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