How Do I Do That in Photoshop?

Create Text?

Get the Horizontal Type tool (T), click it somewhere within your image, and just start typing. You can choose your font and point size up in the Options Bar (when you start typing, it uses the last font and size you used. So, if you want to change your text font, just highlight it first, then choose a new font from the pop-up menu). If you really want to access some serious type features, go under the Window menu and choose Character to bring up a panel with a ton of type controls (baseline shift, superscript, kerning, Open Type features, ...