This guide from Mytour will show you how to invite someone to a conversation on Google Hangouts, either via the Hangouts website through your browser or by using the mobile app on your Android device.
Steps
Using a Desktop Browser

Open the Google Hangouts website on your browser. Type hangouts.google.com into your browser's address bar and hit ↵ Enter on your keyboard.
- If you're not automatically logged in with your Google account, sign in with your email or phone number and password.

Click on the New conversation button (New conversation). This button is shaped like a white plus sign inside a green circle located below the Google logo at the top-left corner of your browser window.

Enter the name, email address, or phone number of the person you'd like to invite. The Search bar will display all relevant matches.

Click on a person from the list. Scroll down to find the individual you wish to invite, then click their name or picture to send an invitation to begin a conversation on Hangouts. A chat box will appear on the right side of the browser window.

Personalize your invitation. You'll see the default message 'Let's chat on Hangouts!' in the chat box. Click on it and type your own custom invitation message.

Click on the Send Invite button (Send Invite). This is the blue button located beneath the invitation message in the chat box. Once clicked, you will see a green check mark and a confirmation message saying 'Invite Sent!' Your recipient will immediately receive your invitation.
Using the app on Android

Open the Hangouts app on your Android device. The Hangouts icon looks like a green speech bubble with white quotation marks inside.
- If Hangouts doesn't automatically log you into your Google account, log in using your email or phone number and password.

Tap on the white + button. This button is located at the bottom right corner of the screen. It allows you to choose between New conversation and New video call.
Tap on the New conversation button. This button looks like a white speech bubble inside a green circle. The Contacts list will then appear.

Enter the name, email address, or phone number of the person you want to invite. The Search bar at the top of the screen will display all matching results.

Tap the Invite button next to a contact's name. This option appears on the right of the contact's photo and name on your phone. A pop-up dialog will appear.

Tap the INVITE TO HANGOUTS button. This option, written in green capital letters, is located at the bottom of the pop-up dialog.

Enter your invitation message. Type a personalized message to invite the person to join Hangouts.

Tap the Send button. The recipient will instantly receive your Hangouts invitation.
