Someone sent some harassing text messages, how to define it legally! What should I do? If I want to sue him, how can I collect evidence!

Item (5) of Article 42 of the Law on Public Security Administration Punishment stipulates that "those who repeatedly send obscene, insulting, intimidating or other information to interfere with the normal life of others" shall be detained for not more than five days or fined not more than 500 yuan; If the circumstances are serious, they shall be detained for not less than five days but not more than ten days, and may also be fined not more than 500 yuan.

If people often send messages to themselves, first save the boring information of harassment as evidence, and then call the police, and the police will accept it.