Douyin sending you text messages may involve the following steps:

1. Verify your mobile phone number when registering: When registering a Douyin account, you usually need to provide your mobile phone number and conduct SMS verification. This is to confirm your identity and ensure that you are the holder of the mobile phone number to prevent malicious registration or abuse.

2. Forgot password retrieval: If you forget the password of your Douyin account, you can choose to retrieve your password through your mobile phone number. During this process, Douyin will send a text message to your mobile phone number, which contains a link or verification code to reset your password, allowing you to reset your password and log in to your account.

3. Security verification and reminders: In order to ensure the security of user accounts, Douyin may actively send text messages for security verification or reminders. For example, when you log in to your Douyin account on a new device, the system may send you a text message asking if you are operating it yourself. This is a way to prevent unauthorized login behavior.

In short, Douyin sends you text messages mostly for security and verification purposes to ensure the security and identity authentication of your account.