I have a Vizio tv an Universal remote Magnavox

[borckmama]

What’s the code

 

[americanaudiophile]

The is no "universal code" for a device for all universal remotes. The code number is just the location in the memory of that remote.
If you don't have a code in the remotes' manual then it probably doesn't have codes for Vizio. Some remotes do have a way to try the codes it does have just in case they are the same for different brands.
The Logitech Harmony remotes are programmed from their online database. You can check that they have the codes for your set before you buy one. If you have the original remote they will prompt you to teach the codes into their database. That's how they add new devices.