Black Outline for Text help?

So i was following this tutorial
and this person showed me how to create a black outline
for a 3D text

Here’s my finished text

However, when I click F 12.
The text remains the same- basic.
And I don’t see any black-outline.

How do I fix this?

You should connect the output of the multiplier-node to the composite node. (I guess the composite node is the one cut off in your screen shot)

Currently the output is connected to a view node. That is why the outline shows up in the upper window but not in the rendered output.