I'm a Project Manager at an Architectural Firm specializing in Custom High-End Homes. 

I've looked into 6+ including calling and experiencing the customer service myself and have not found one that seems reliable.

PayRange seems less expensive, but customer reviews for users seem overly negative. 

Navigating the Surge in Rental Application Fraud: A Guide for Landlords and Property ManagersIn recent years, the rental market has experienced a troubling rise in application fraud.

Every little thing in the project should be in writing, even down to the door stops :-) See my tile spec sheet below ...Two problems with your post though - 1) In my experience, most problems come from the customer changing their minds constantly.

But I need a portal where I can do the following -Customize the tenant application  ( Cozy does not  allow me to customize)- Have tenant Upload Pay stubs, DL, etc. 

I figured why not just use a banks money instead of using a customers money and not have to deal with picky customers.

well, there are gurus and wannabes that's for sure, but if everyone did some research they could figure that out and get the right people to guide them.

This is not only my experience, but when you call VRBO or Airbnb customer service, they will tell you the same thing.  

I started by patching about a dozen (not small) holes in the wall, re-doing all the drywall in the bathroom, installing new shower plumbing, putting in recessed lighting, installing seamless LVP throughout, texturing/priming/painting all walls, installing new 5 inch pine baseboard all around, and installing custom bathroom vanity/pantry cabinets, and hanging new custom shaker doors in the kitchen.