Chris,I have 2 brownstones and found the easiest and cheapest solution as follows:Smart lock (I recommend Schlage) with each tenant receiving app access and code.

I received a lot of pushback from my tenants not wanting to trust some random App Platform they had never heard of when I attempted to convert to software.

@Andrew Postell, sorry for whatever reason, the mobile app on Android was not resolving your name tagging. 

I just text handymen or whoever to go fix things when they break, then cash app or zelle them $.

Depending what state you're in there may be an app/website to go to and review.

They are combo locks & their app integrates with ESS, so the unlock code shows in ESS. 

Don't need more phone apps.

Confirm that the Debt Service Company used, will provide you with easy access to:      - monthly/quarterly/annual statements of your pymt history    - ideally, easy user login web or app access     - 1098 or annual (interest payment) tax documentation mailed, emailed, or pdf download-able     - alerts, notifications, and pymt scheduling options for: pymt due, pymt applied/received, outstanding balance, etc.3.

On the app, I also ask for their direct supervisor's work LANDLINE, as well as their work email. 

They also have an app that will allow you to make and receive calls from those numbers.