My iPad Pro 10.5 has completely replaced my MacBook Pro (which I have sold). I own a small music production company, and here is my workflow:
1) I have an Office 365 subscription for my company email, and this gives me use of Word, Excel, and OneDrive. I use Word for typing contracts and the occasional letter or envelope that I need to print. I use Excel for keeping track of music metadata on spreadsheets and manipulating the metadata for different systems and distributors — all of which require metadata to be in different formats.
2) I use Documents by Readdle for file management. I keep all my business files in iCloud Drive, and Documents keeps all those files synced locally on the iPad as well. Then once per month I zip the entire folder (with all my business files) into a single zip file. I rename the zip file with the date, and copy it over to an Archive folder I keep on OneDrive. This is how I backup my files. I also use Documents to upload & download music files from FTP sites on a daily basis.
3) I use AudioShare for my audio file management. I keep all music we have released here, each album’s files in a separate folder, and all of these folders in a folder labeled “Archive”. Then any albums that I am currently working on get put in their own folders outside of the Archive folder. They get transferred to the Archive folder once they are done and released. Each one of these album folders also gets zipped into a single zip file and stored as a backup on OneDrive, and copied to our FTP site to be available for our distributors to download.
4) The Files app allows me to move files between Documents (locally stored files in Documents), iCloud, OneDrive, and AudioShare (locally stored files in AudioShare) just by dragging and dropping — no “Share” menu workarounds needed.
5) I am able to use Safari to register copyrights at copyright.gov and can upload the music files directly from AudioShare from within Safari.
6) I use PDF Expert (by Readdle) to sign contracts, and to complete any PDF forms that are needed for any other purpose.
7) I use Scanner Pro (by Readdle) to scan anything I receive in hard copy, so this way all my business files are stored electronically.
For email, I just use the Apple Mail app. I find this works perfectly and have not felt the need to try using Outlook or any other third party email apps.