Hey there, @Koizumi008. Happy to provide some insight here.
I have some good news to share with you about the attachment feature in QuickBooks Online.
Since QuickBooks Online is a cloud base, there isn't a storage limit on attachments and other selected data. That said, it's unlimited storage for this feature.
Check out these articles to know what transactions can keep attachments and acceptable characters in QuickBooks:
Feel free to visit our QuickBooks Global Help Articles for your future reference. This page contains various topics on how to manage your business like banking, customers, vendors, taxes, and other matters.
Please don't hesitate to let me know if there's anything you need. I'm always up to talking about QuickBooks. Thanks for reaching out, and have a wonderful rest of your week, Koizumi008.
