Can I upload changes to a single field to all my customer records? It could be the fax or 'other' field, so we can cross reference an account number from our CRM system?

Welcome to the Community, Paul.

I'll provide information about uploading changes to a single field in all customer records in QuickBooks Online (QBO).

At the moment, the feature to change the Fax and Other fields in QBO is unavailable. However, if you'd like to have the option to make changes to a single field for the customer records or profile, I encourage you to share your thoughts and suggestions through our feedback channel. Our product developers are open to suggestions to improve our products and meet our customer's business needs.

Here's how:

1. At the upper right corner, click the Gear icon.
2. Under the Profile, select Feedback.
3. Enter your comments or product suggestions.
4. Then, select Next to submit a feedback.

For future reference, you can check this article to guide you when generating the sale by customer detail report: Run reports in QBO

Please don't hesitate to ask if you have any other concerns about uploading changes to a single field to all customer records. I'm always here to help, Paul. Take care.