Hello everybody ! Finally , i found a solution for this today !! Hopefully it will work for you. I'm using a Mac, so i don't know if is going to work on Windows...
I use the app downloaded from the appStore, which doesn't have the 'codeblock' option. To my surprise, i try to use Evernote entering from Safari, and it has the 'codeblock' option !! So, this may be an immediate solution...
However, i wanted to have this on the desktop app, so i do this:
Close everything relationated with evernote. Delete the app from your mac ( right click on the application --> remove ).
Open Safari
Go to https://evernote.com/
Click : "download the app"
Wait for a second. It should be downloading the app
Of course, then, install it
Now you have the desktop app (again). Open evernote, log in with your user, and go to preferences/software uptade ( or similar ) --> activate the codeblock checkbox