PowerApps Workflow Development

I need a PowerApps workflow for the Microsoft standard meeting template, with added attachment features and integration across four Microsoft sites/groups.

Requirements:
- Implement additional attachment features:
- Drag and drop attachments
- Attachment preview
- Multiple file types support
- Set up workflows for:
- Approval process
- Document sharing
- Task assignment
- Integrate across:
- Teams
- SharePoint
- OneDrive

Ideal Skills and Experience:
- Proficiency in PowerApps
- Experience with Microsoft Teams, SharePoint, and OneDrive
- Strong understanding of workflow automation
- Familiarity with attachment handling in PowerApps