The company has to pay insurance, how to write a notice to the employees?

This is easy to write, can you write it like this:

notification

In order to implement the requirements of laws, regulations and government documents, the company decided to buy social security for each employee, which is the company's concern for employees and the embodiment of the company culture. No employee can shirk it without proper reasons. If he has purchased social security from other units or individuals, he must provide insurance invoices to the company so that the company can handle social security for other employees in time.

Hereby inform you

XXXXX company XXX department

X year x month x day

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.