Thank you for posting here in the Community, @claudia-escriban.

We want help you update your bank transactions using Excel CSV. However, we need more information about it to provide the right resolution and to get this sorted out promptly.

Did you get an error when uploading the data via CSV? If so, I recommend reviewing the file from your bank and ensure the format is correct.

Currently, QuickBooks supports a 3 or 4 column format for your banking data. For more information and detailed instructions, please go to this link: Import bank transactions using Excel CSV files.

After checking the format, you can follow these steps to import:

1. On the left panel, go to the Banking menu and select Banking.
2. Click File upload. 
3. Press Browse and choose the file.
4. Select Open, then hit Next.
5. Follow the instructions until finish, then select Let's go!.

Also, I've attached an article about importing transactions, like how to fix bank upload errors in QuickBooks: Fix bank upload errors in QuickBooks Online.

Please know that you're always welcome to post any questions you have in this space. Have a great day ahead.