From: Daniel Piechnick
Hi again Shaz. In Photoshop, when you use the Text Tool, it makes a text layer. These text layers have a "T" next to them. You can go back and change the font, size, colour, boldness etc of these layers, because they're saved as a text layer. If you want to edit a text layer as if it were a normal layer, you'll have to right-click on it, and click "Rasterize" or "Render Layer", depending on which version of Photoshop you're using. Rasterizing/rendering a layer is irreversible though. After Rasterizing/rendering the layer, Photoshop will just look at the layer as an arrangement of pixels, and has no way of reading it as text later, even if it looks like text to you.
