I know that there is a TTS ability in MOON+ Reader Pro. Can someone explain me exactly how I can TTS a ebook with MOON+ Reader Pro. I don't see any option or speak button.
You find it in the options, in the "control" section. If you tap on an action (e.g. for "shake"), a drop-down opens where you can select many things -- a.o. Read (Text-to-Speech). If you enable it here and then shake the device, Moon+ will start to read the text to you. Shake again to make it stop.
You also can assign it to your DPad keys, or the headset controls (just scroll further down on that page to see for yourself).
The best way to do this: At the bottom of Miscellaneous Options page, there's an option Customize Reader Bar Icon. Tap it and check Speak.
Now, you can easily access TTS from bottom bar.