If you allow others to search or preview, they may be able to view your personal information. However, you can manage these permissions yourself:
Path: Me > Settings > Privacy > Methods for Adding Me
Here you can enable or disable different ways for others to add you as a friend, such as:
Disable WeChat ID: Other users will no longer be able to search for you using your WeChat ID.
Disable Mobile number: Other users cannot find your account via your phone number. Even if your number is saved in their contacts, your account will not appear in Friend Recommendations.