It depends on what you are looking for.

Reports, Journal Entries, All will show you who posted what.

Reports, Banking, Cheque Log/Direct Deposit Log will show you all cheques/payments posted and/or printed.

Edit: Change menu to correct path.

I am looking at checking on when users have logged in and out of Sage, like a User Log

There is not one for this to my knowledge.  It will tell you under File, View All Users, who is logged in now but not who logged in/out and when in the past.