Hi there, sdm6612.
Your Missouri Withholding Account Number (8 digits) is different from the Missouri Employer Account Number for state unemployment (10 or 14 digits).
To get your Employer Account Number, click the links in the Help for New Employers section or visit their website. Let me share these links for more details:
Let me know if you have follow-up questions. I'll get back here to help you further.