The executable file (Ssms.exe) for SQL Server Management Studio is located in different locations depending on the version of SQL Server.
For SQL Managment Studio 18
C:\Program Files (x86)\Microsoft SQL Server Management Studio 18\Common7\IDE\Ssms.exe
For SQL Server 2017:
C:\Program Files (x86)\Microsoft SQL Server\140\Tools\Binn\ManagementStudio\Ssms.exe
For SQL Server 2016:
C:\Program Files (x86)\Microsoft SQL Server\130\Tools\Binn\ManagementStudio\Ssms.exe
For SQL Server 2014:
C:\Program Files (x86)\Microsoft SQL Server\120\Tools\Binn\ManagementStudio\Ssms.exe
For SQL Server 2012:
C:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\ManagementStudio\Ssms.exe
For SQL Server 2008 R2:
C:\Program Files\Microsoft SQL Server\100\Tools\Binn\VSShell\Common7\IDE\Ssms.exe
For the older SQL Server 2005 instances SSMS file was called SqlWb.exe and it’s located at:
C:\Program Files\Microsoft SQL Server\90\Tools\Binn\VSShell\Common7\IDE\SqlWb.exe