Running same report package for multiple Entity

I have 1500+ Entity and each entity owner is responsible for creating a standard report every month - this report has P&L data coming from Planning instance and a lot of commentary is provided for different lines. Currently we are using excel where : Each user pull data from Planning, put comments in excel and export it as PDF (offline process). I am planning to switch to Narrative reporting and use Notes feature. I also wanted to have a workflow process so each entity submit the information to Regionals and so on within NR so i have end to end