In process of installing Adobe CS6 and asks close application SafariPlugInUpda

It seems the message should read, close application SafariPlugInUpdate

Meaning, the Adobe installer is waiting for you to close a running application before it can proceed. Why it needs an update like that closed is a question on its own. But regardless, it wants you to first close the other process.

If you can't find the plugin process to force quit or close it, restart the Mac and try the CS6 installer again.

MacOS Big Sur 11.* only supports 64-bit applications and the ancient Adobe CS6 Suite has 32-bit components and dependent upon 32-bit Java code (Java 6).

Adobe CS6 was only somewhat functional with macOS Mojave (10.14.6) and no later version of macOS. Now, you will need to use an older Mac running macOS Mojave or older for CS6, determine if you want to pay Adobe a subscription fee for a current product on Big Sur or choose alternative software such as the Affinity product line which is non-subscription and quite powerful for a sub 100 USD price point.

Sorry, I misread your post as I was up most of the night and saw this with bleary eyes. See Kurt Lang's response.