I CAN USE A QUICKBOOKS ONLINE FOR HOW MANY COMPANIES?

We can have one company per subscription policy only for the regular QuickBooks Online plan, Sura.

Since you're handling a bookkeeping company, it is advisable to use QuickBooks Online Accountants (QBOA) to manage multiple clients.

Before you can add them to your QBOA account, your clients will need to separately subscribe to a version of QuickBooks Online, choosing from options like Simple Start, Essentials, or Plus, based on their specific business needs.

After your clients have already set up their QBO subscription, I'll share this page on how to send an invitation link to your client: Add clients to QuickBooks Online Accountant.

After your client accepts the invitation you sent, QuickBooks will link your firm's account with your client's account. This connection will allow your client to access and review your books in detail: Open and review clients' QuickBooks Online or Self-Employed accounts.

Revisit this thread or create another discussion for any other concerns you may have.

@suraporn 

Where are your clients located? UK or Thailand?