Access controls on the platforms you already pay for.
Admin role review, multi-factor authentication where the platform supports it, and a look at who can reach shared mail and files. The goal is fewer standing admin accounts, not a promise that a breach cannot happen.
In a typical scope
- Admin role review
- Multi-factor authentication setup
- Who can open shared mail and files
- A short list of what was changed
This is configuration of Google or Microsoft controls. It is not a security audit, a compliance certification, or a guarantee against compromise.