You can invite your accountant into your QuickBooks Online account through the Manage Users section. Let me show you how.
Click on the Settings Icon at the top right.
Click on Manage Users.
Click on the Accounting firms tab.
Click on Invite.
Enter your accountants information.
Click on Save.
Your accountant will receive an email notification asking her to completely accept the invitation as an accountant. Once completed she should be able to access your QuickBooks Online file as an accountant user.