I will develop outlook addin for office365

If you are seeking an application that can integrate with Outlook, Word, and Excel. Here is the gig you are looking for.

I write an application to Integrate your application with Office 365. This will add Add features, and buttons to Outlook.

The benefit is One plugin for Office 365 web, Outlook 2013/16/21/19 desktop, add-in for MAC for Android, and iPhone. You don't need to write multiple applications for different platforms.

Please before buying the gig contact me to check whether I understand your requirements better.