Zoho Sigma is a platform enabling developers to create and host extensions for various Zoho applications. These extensions, enhancing service capabilities, are built using languages like HTML, JavaScript, and CSS, with support for server-side operations. Sigma facilitates connections between Zoho apps and third-party platforms. Zoho Marketplace serves as a centralized hub for these extensions, allowing free or paid publication. Users access and install these extensions seamlessly from the Marketplace, ensuring unified management and simplified onboarding amidst organizational expansion.