This article explains how to make text bold or italic in Photoshop versions 5.0 and later.

Select the menu tab on the Tool Options bar to open the Character palette. If it is not already visible, go to Window > Character.

Select the text you want to bold or italicize by highlighting the words. Select the 3 horizontal lines in the upper right corner of the palette menu.

You should see options for Faux Bold and Faux Italic. Choose the one you want — or both.