If the 10.6 installer lists 10.6.1 as an option, download that version instead. The installation process is identical.
: You must have a valid, paid license or a trial license assigned to your account to see the download options. If you do not see these options, contact your organization's Esri license administrator . ArcGIS Desktop 10.6.1 quick start guide download arcgis 10.6
Before reviewing the software, we must address the act of downloading it. The Complete Guide to ArcGIS 10
Once the installation finishes, the will open. No new security patches
: Version 10.6 focused heavily on performance improvements and bug fixes.