Allow me to provide some information about customer email character spacing via QuickBooks Online.
Each field in your QuickBooks file has a maximum number of characters that can be entered.
Item name may contain special characters but it is recommended that the first character not be a special character. While the Memo field can contain 4095 characters, only 30-60 characters will display on printed checks depending on print settings. 96 characters will display on a Transaction Detail report. While the Notes field on the timesheet can contain 4095 characters, only 96 characters will display on the Time by Job Detail report.
This article lists the maximum number of characters in each filed especially in the customer fields: https://quickbooks.intuit.com/community/Help-Articles/Character-limitations-for-fields-in-QuickBooks....
Should you have more questions about customer's email character spacing in QuickBooks Online, please let me know. Have a great rest of your day.