Making rental applications before or after 1st purchase

[Steven Mitchell]

Hello All, 

Should I make my rental application before or after I get my first rental property investment? I understand there will be unique aspects of each rental property that I will need to fill into my application but not sure when to make these document . I have been reading Brandon's book on property management, landlording on autopilot, and every landlords legal guide to get my knowledge base down. Any guidance would be helpful. Steve