A Microsoft file hosting and synchronization service.
Hi! If what you mean is merging multiple Microsoft accounts into one single account (so that all data, history, purchases, and subscriptions from the other email addresses are combined into one), that isn’t supported.
What you can do instead is:
Manually transfer your files/data (for example, move/copy OneDrive files, export emails/contacts where applicable, etc.).
If there are subscriptions on the accounts you won’t keep, you’ll need to cancel them on those accounts and then purchase/activate a new subscription on the account you want to keep.
If you plan to delete any of the accounts, make sure you transfer anything you need and handle subscriptions first, because once an account is deleted you wont be able.