When adding HR WeChat, you need to send a friendly and concise greeting message to let the other party know who you are and what you want to do. Here are some examples:

1. If you have submitted your resume and want to apply for a specific position, you can say hello like this:

Hello, I'm [your name] and I'm here to apply for [specific position]. I have sent my resume and look forward to the opportunity to further discuss my abilities and experience.

If you haven't applied for a specific position, but want to know more information from HR, you can say hello like this:

Hello, I'm [your name], and I'm very interested in your company's [specific position or project]. I want to know more about this opportunity.

3. If you have already communicated with the HR of another platform and confirmed the time or place of the interview, you can say hello like this:

Hello, I'm [your name], and we have confirmed the interview arrangement by phone or email. I'd like to reconfirm our schedule and ask if there are any additional information or instructions to prepare.

In either case, your message should be concise, friendly and explain your purpose. At the same time, don't forget to wait for HR's reply after sending the message.