It's easy to add properties into the DealMachine app even though you're not in front of the property.
Click Map View and start typing the address you're wanting to add on the top bar. As you do, the app would show suggested addresses.
Just continue typing until you get the address you want, tap it(the address) and then click the "add lead" option so it gets added to your leads list.
Here's a short video where Elise shows you how it's done.
Hope this helps! 😉