Final answer:
The 10-digit NPI number for the service provider should be entered in Box 24J of the CMS-1500 form, which is necessary for the processing of health insurance claims.
Step-by-step explanation:
The 10-digit National Provider Identifier (NPI) number for the provider who performed the service should be entered in Box 24J of the CMS-1500 form. This box is situated in the lower portion of the form, on the right-hand side, specifically designed for the rendering provider’s identifier. It's important to ensure that the NPI is entered correctly, as it is necessary for the processing and payment of health insurance claims.