Hey there, Elizabeth. It’s great to see you taking the initiative to enhance your spreadsheet capabilities. I'm here to assist you with this task and ensure you can achieve your goals.
You can't find the Select custom field columns option because the sheet is protected. To unprotect it, you'll need to enter the password. This is the one specifically set for that Excel document, not your QuickBooks or computer password. I recommend coordinating to the person who created or last modified the document. They should be able to provide you with the password.
If it doesn't work, I recommend contacting our technical support team for further assistance. They can help you resolve password issues, add custom fields, and troubleshoot any technical problems with your account. You can reach them by signing into Spreadsheet Sync and selecting Help, then Contact Us. Our dedicated team is available Monday to Friday, 6AM-6PM PT.
For more detailed guidance on editing your record templates, visit this article: Import data using Spreadsheet Sync in QuickBooks Online Advanced or Accountant.
To help you manage Spreadsheet Sync better, I’ve also included an article on some common questions: Frequently Asked Questions about Spreadsheet Sync in QuickBooks Online Advanced or Accountant.
You can always return and drop a comment if you need more help, Elizabeth. I'm here to support you every step of the way. Take care and have a great day!