Can i import 45 classes in one time or i should add one by one

Hi, Hicham. I'd be pleased to share information regarding your inquiry about importing classes to QuickBooks Online (QBO). 

I understand how important it is to transfer essential business data to streamline your workflow. QBO allows you to seamlessly import data such as bank transactions, customers, suppliers, chart of accounts, products and services, invoices, bills, and journal entries. However, the direct import of classes is not supported at this time.

On the bright side, third-party applications offer an efficient solution. You can explore apps that you can integrate to QBO which provide the required capabilities and are designed to handle tasks like importing classes in bulk. Follow these steps to locate an app in QBO:

1. Sign in to your QuickBooks Online account.
2. Select the Apps tab on left navigation bar.
3. Search for the app you wish to connect to in the magnifying glass bar, or select the Browse category ▼ to search for an app by category.

Also, here's an article that discusses the frequently asked questions about this topic: Common questions about importing data to QuickBooks Online.
 

Lastly, I'd like to share this article for future reference if you want to make any changes to your classes: Create and manage classes in QuickBooks Online.

Keep the questions coming if you need further assistance about classes. I’ll check back in, and our Community pros are also here to help. Stay well.