If you conduct retirement pension education using materials from a financial institution, how do you keep proof of completion?

Hello, I am in charge of mandatory legal training in the HR team.
For retirement pension subscriber education, we receive educational materials from our financial institutions and provide guidance to our employees.
We are not conducting training by inviting a separate instructor; instead, we are proceeding by sending materials via email or providing links to online training.
In this case, I am wondering what kind of records the company needs to keep to prove that the training was conducted.

Do I just need to keep the educational materials and the emails sent?
It is also unclear whether we need to separately check whether each employee actually verified the data.
If you complete the course online, a record of completion is kept, but there isn't anything like that when the materials are sent via email.
I am curious to know what materials you typically receive and keep at the end of the year for places that outsource training to financial institutions.