I don't know what that means by "10-digit customer ID number."
[ADDENDUM: I see @ Mike9241 explained it above while I was typing. 🙂 ]
If you are trying to register an IRS account, here are the criteria needed to register as listed on the IRS website.
You need:
- your SSN, date of birth, filing status and mailing address from latest tax return,
- access to your email account,
- your personal account number from a credit card, mortgage, home equity loan, home equity line of credit or car loan, and
- a mobile phone linked to your name (for faster registration) or ability to receive an activation code by mail.
