How to export a file in Adobe Illustrator and still have it be a vector?

I am new to Adobe Illustrator. I created a simple image with a shape and some text and wanted to create a vector image. So I basically created the shape and the text. Then right-clicked and selected "Create Outlines" from the drop-down menu, which did create outlines.

Then I went ahead to export the image as a .png file. It was saved. But the problem is that when i open it with Windows Photo Viewer and increase its size, it becomes pixelated. So what should I do to make it a vector?