Ask ten founders what their company registration number is, and half of them will read out the CIN, and the other half will look confused. The two are closely related but not the same, and confusing them can cause small but annoying problems on bank forms, tender documents, and MCA filings. Here’s a good way to think about their relationship. https://www.corpzo.com/company-registration-number-and-cin-what-they-mean-and-how-to-get-them