There are several ways to customize and extend solution using third-party applications like Microsoft 165 apps for businesses and services. The first option is to install apps and add-ins from the Microsoft AppSource marketplace, which includes solutions for various industries and needs. Additionally, developers can create and publish their apps using the Microsoft 365 developer platform, which provides APIs, tools, and documentation. Other options include integrating Microsoft 365 with other cloud services and applications using connectors and APIs and using Microsoft Power Platform to create custom workflows and business processes. Personalizing and expanding Microsoft 365 with third-party solutions can help businesses improve productivity, efficiency, and collaboration.