SH-7 form is a return that a company must file with the Registrar of Companies (ROC) when it alters its share capital or the number of its members, or increases its share capital due to the conversion of debentures or loans as a result of an order from the Central Government. This return must be filed within 30 days of such alteration or increase.
In simpler terms, it's a notification to the government about changes in a company's fundamental capital structure.
