Yes, you can send iMessages from an iPhone to an Android (and vice versa) using SMS, which is simply the formal name for text messaging. Android phones can receive SMS text messages from any other phone or device on the market.

Can I send an iMessage to a non Apple device?

iMessage is from Apple and it only works between Apple Devices like iPhone, iPad, iPod touch or Mac. If you use the Messages app to send a message to a non-apple device, it will be send as a SMS instead. If you cannot send a SMS, you can also use a third-party messenger like FB Messenger or WhatsApp.

How do I send messages to non iPhone users?

Go to Settings, then Messages, then Text Message Forwarding. It will show you a button to turn on and link a device, such as your MacBook. This will have no effect on your ability to send a text to a non-iPhone user from the iPhone. It will enable you to send and receive texts to non-iPhone users from your computer.