How do I send messages on my Mac Air to android phones

In order for your MacBook Air to send text messages to an Android phone, or any other phone, you need to have an iPhone that will forward them for your notebook.

The support article you came here from should provide you with the steps needed to try to resolve this issue. Have you tried them all yet? If so, and they didn't help, I suggest that you contact Apple Support directly. To do so, simply select the "Get Support" link in the upper right-hand side of this forum's web page.