To begin adding friends in WeChat, start in the 「Contacts」 tab and press the icon at the top right. You can then add friends to WeChat via the following ways:
1) Search by your friend's WeChat ID or phone number.
2) Add from mobile contacts. You can see which friends are already using WeChat from your phone's mobile contacts then add them.
3) Add from social media networks, including Google and Linkedin.
4) Add via Friend Radar. Easily add friends who are in your immediate vicinity so that you don't have to waste time getting people's numbers.