QQ mailbox is a kind of e-mail, which can be added. In fact, it doesn't matter whether you add your resume or email, but some high-tech companies will look at your working hours according to this. For example, in the early days, Netease's free mailbox was only three letters long, and later it was changed to more than six letters for registration. If you can have a Netease mailbox with less than six letters, people who work long hours can see how many years of experience you have.