Hello again, Aengineering.

At this time, the option to lock in the resized box in the Customer Details tab and resize the note section on the Customer notes field is not an option in QuickBooks Online. I recommend sending this request straight to our product engineers through feedback. Sharing features and options that you would like implemented is how our engineers look for new product updates.

To send feedback, follow the below steps:

1. Go to the Gear icon at the top.
2. Select Feedback.
3. Enter your comments or product suggestions. 
4. Then select Next to submit feedback.

You may also visit our Feedback forum page. From there, you can see a list of other QuickBooks users who already suggested this feature, as well as the recent updates in QuickBooks.

In the meantime, let me share some resources that you can browse and use as a reference in managing and navigating around your QuickBooks account.

•  Video Tutorials for QuickBooks Online - You can watch videos that can help you perform the most vital features of the program. 
• Small Business Webinars and Trainings - Join our live QuickBooks webinars for more in-depth knowledge on how you can maximize the use of QuickBooks to manage your finances.

Feel free to reach out to me if you need anything else. I'll be here to help. Have a good one!