how can i add accountant when i am on trail of 30 days as manage user does not shows any accounting firm tab?

Hello there, @ad121.

Let's use the Company admin user type so you can add your accountant in QuickBooks Online (QBO) and help you manage your books and accounting data accordingly.

The Accounting firms tab, where you can add an accountant, is only available to selected QBO International versions. With this, you'll have to add an accountant as a user (Company admin) to your account. Then, make sure to select the This user is my accountant option to indicate that they're your accountant.

Please note that you can only have one accountant user and they doesn’t count toward your user limit. Whenever you're ready, follow these steps:

1. Go to Settings ⚙, then select Manage users.
2. Click the Add user button.
3. Select Company admin, then click the This user is my accountant box.
4. Click Next. 
5. Enter your accountant’s name and email, then Save.

Once you're done, your accountant receives an email with steps on how to connect. For the complete guide, refer to this article: Add an accountant to review your accounting in QuickBooks Online.

Also, you may want to check out this article as your reference to learn more about the different options for user roles and access permissions in QBO: User roles and access rights in QuickBooks Online.

If there's anything else you need in adding accountant users in QBO, don't hesitate to comment below. I'm always here to help. Take care, and stay safe, @ad121.