My company issues invoices to others, and now he has sued a person. How did our company receive a court summons?

Maybe the other party also sued you, or the court may add you ex officio to find out the facts of the case;

Litigation is not only professional, but also procedural, which requires practical experience. When encountering specific legal affairs, it is recommended to consult a lawyer in person and entrust a professional lawyer to handle it as much as possible.