Open any friend and enter the interface for sending messages, and then follow the steps below:

1) Click "+" on the menu bar (Figure ①) -> Emoticon -> Symbol Emoticon ( Figure ②)/QQ Emoticons->Select one or more emoticons you like. Next press and hold the input box until the option is copied. Select the emoji you want and copy it. (As shown in the picture below)

2) Go to WeChat Settings->Personal Information->Name. (As shown in the picture below)

3) Press and hold the input box until the paste option pops up, click paste and save, return to the previous interface and you will see that emoticons have been added to the name.

(As shown in the picture below)