Cam I access emails and documents created under a business subscription using my personal Microsoft account?

Hello,

You can't. Anything stored in Microsoft 365 Business belongs to that work tenant and is tied to that work account. To keep access, move what you need before you close it.

Do this while the business subscription still works:

First, sign in to each PC and make sure you also have a personal sign-in on the device, for example add your personal Microsoft account or a local admin in Settings > Accounts, then sign in once so you are not dependent on the work sign-in later.

Next, copy any local documents from the old work profile into your new profile so those files stay on the PC.

For cloud files, open OneDrive for Business and either download everything to a local folder or sync both the work OneDrive and your personal OneDrive in the OneDrive app, then copy the folders across.

For email, use Outlook for Windows to export the work mailbox to a PST via File > Open & Export > Import/Export > Export to a file > Outlook Data File (.pst). Add your personal Outlook or other personal mailbox to Outlook and drag the folders from the PST into it to upload.

For SharePoint or Teams files, open the libraries in a browser and use Sync or Download, then place the copies in your personal storage.

If you still expect mail for a short time, set a mailbox forward and an automatic reply on the work mailbox to your personal address until you shut the tenant down. When you have verified your copies, you can cancel. Microsoft will remove the tenant data after a short grace period, so do not rely on later access.

Let me know if this helps!