HI Jain,
You need to set up your product type for Alert Management in that node. Once you do that, when you run the Tcode FTR_ALERT based on upto and including date, the system will show you all the un posted flows based on the due dates. from here you can send notifications to the users manually.
You have to assign users in Define Alert Categories. You also need to check Basis settings to send notifications as usually these are blocked in PRD.
There is no separate category for maturity or interest flows, it shows all the due flows for a given key date. 
If you want a more detailed notification , you will have to create your own program and make it run in background which will check the flows due for each day and send the notifications.
Regards,
Nikhil