Recently, I was asked to change the "View Columns" on CRM Global Search. Typically, there is no seperate view for Global Search. It works on Quick find view of the configured entities for Global search, where it looks for "Find Columns" to run its quick find searches. So, I started looking into Quick find view. After little bit research, I found Global Search shows first three columns of Quick Find view in the searches. So I just changed the order of the few columns, moved the requested View Columns to first three and Voila! its done.