If you are still figuring out the Inspector (which is the better way to fix this), there is another way to change the font colour. Select your text. Press and hold the Command key (will likely have 'command' and/or a funny symbol that looks like a rug beater). Anyway, press and hold the Command key, and then press and release the 'A' key, and release the Command key. This will select 'All' the text including the stuff you can't see. Then Control-click (or CTRL on some keyboards) anywhere on the highlighted text.
You should see a dropdown menu. Look down the list, and click on the triangle to the right of "Fonts". Sometimes just hovering your cursor on the "Fonts" line is enough. Another dropdown menu should appear with a "Show Colours" line. Click on this and the Colour Palette should appear. We suspect (gauchogolfer and I) that your font is now set to White. Pick another colour and all should be revealed. Hopefully.
Good Luck.
ps PeggyD has also weighed in. Listen to her. She knows what she is talking about.