Forum Moderators: not2easy
You need to click on the text logo in the floating toolbar, then click a location on the image, the text box opens up, you can choose your colour, font etc and position the text exactly before clicking on OK to finalise the text. Do it in a new layer to be on the safe side so you can delete the layer if you don't like it. But all that applies to PCs. Photoshop is probably not much different on a mac.
After you've opened the image click on "T" and then click anywhere in the image. The Type Tool dialogue box will open and will have a drop down box to choose fonts.