need add new user, when I going to add new user message appearing \"You’ve reached your company limit of 5 billable users\" what should I do for add a new user

You can consider upgrading your QuickBooks subscription to include more user licenses to your account, Fazil1.

Since your current subscription allows up to five billable active users, upgrading to a higher QuickBooks version enables you to add a new additional user.

1. From the previous account, sign in to QuickBooks as a primary admin.
2. Go to Settings and select Accounts and Settings.
3. Make sure your payment info is up to date.
4. In the QuickBooks Online section, select Upgrade your plan.
5. Review the available plans and then select Choose plan.
6. Follow the on-screen steps to upgrade your plan.

In case you need to grant access to your accountant, please refer to this article for guidance: Add accountant users in QuickBooks Online.

Let me know if you have other questions about managing users.