I want to write a simple Python script using Selenium to scrape information from a website but in collaboration with a (standing by) human user who at some point will provide information in the browser. 
How do I get the following behaviour from the script:
Wait until the human user 

enters information (such as login details)
submit the information

then (and only then) do something with the page loaded after human submission.
Let's pretend, that it isn't a human user, who enters the information and submits it, but it all is done automatically with some delay. How would you handle it then? I guess, that you would wait for a certain element to appear or the page something. The same procedure does work with the human user, only wait times may be a bit longer.
Selenium to interact with human user to provide login information