Keep what retention rules require, delete what you are obliged to delete, and license a copy of the rest before the email, drive and software accounts are cancelled. Once the subscriptions lapse the records are gone, and they are often the last asset with a price.
Before you cancel anything
Google Workspace, Microsoft 365, Slack, the CRM and the ERP delete data on their own schedule after a subscription ends. Downgrade or archive rather than cancel until you know what the records are worth.
What you must keep
Tax and payroll records for the periods an authority can still examine, employment records, and anything under a litigation hold or a regulator's request. A licence is a copy, so none of this has to leave your hands.
What a buyer pays for
Years of real people doing real work: mail threads, quotes, jobs, drawings, tickets, the shared drive. A company with 50 or more staff and three years of records is in range. A closed company is often the cleaner licence: nothing is still being added and the rights are settled.
Who signs
The directors or officers winding up, or the trustee, liquidator or assignee if one is appointed. Proceeds go to whoever the wind-down pays first.