VB doesn’t have such a construct at the language level. It has single line comments using apostrophe character:
' hello world
' this is a comment
Rem this is also a comment
However, Visual Studio has a functionality to automate this task. Select the lines you want and press Ctrl+K+C for commenting and Ctrl+K+U for uncommenting (General Development Settings shortcuts, look at the “Edit -> Advanced” menu while selecting some code to see the shortcuts).