Want to send an invite for Google inbox to someone else but don't know how to do it? Don't worry!
Actually, I myself didn't know how to do this. I tried googling it but got no relevant information. Somehow I stumbled upon this, and got to know how to do it. So, this is a small instructable for others who have a similar problem. :)
Click on the plus symbol button, which will show multiple options on selecting it.
Click on the invite to inbox button.
Send it to any e-mail address you wish to send an invite!