Integration is an important part of a Solution Architect's designs. The business app can integrate data, applications, and processes between corporate apps (intranet or legacy), various identity applications and services, collaboration services (SharePoint, Teams, Voice apps, etc.), social, business processes, and data.
You need to use Power Apps to create a mobile app for a sales team. Then you add Power Automate flow to send an email to the customer. You need to install the data gateway on- premises to connect to SharePoint. Power Automate uses this connection to add an invoice to SharePoint. And finally, post a message to Microsoft Teams. This flow will be triggered manually when a person submits a customer order in a mobile app.
Reference:
https://docs.microsoft.com/en-us/learn/modules/integrations/1-introduction
https://docs.microsoft.com/en-us/data-integration/gateway/service-gateway-onprem
https://docs.microsoft.com/en-us/power-platform/admin/set-up-sharepoint-integration
https://docs.microsoft.com/en-us/microsoftteams/teams-power-platfom-integration