Worked on the MicrosoftDocs/microsoft-365-docs repository to develop an external collaboration guide for Microsoft 365 setup, focusing on B2B and multitenant environments. The documentation detailed secure sharing of applications and services with external users while maintaining strict data and access controls. Updates were made to existing setup guides to incorporate best practices for cross-tenant deployments and secure sharing flows. The work was delivered using Markdown and emphasized clear, actionable instructions for IT administrators. This contribution addressed the need for comprehensive, up-to-date documentation, enabling organizations to implement secure external collaboration in Microsoft 365 environments with confidence and adherence to security standards.