How do you make codes to make accounts that can interact?

Hello! I want to create an app where if one person presses a button, it changes a variable on another person’s account page.

person 1 presses return
not returned changes into returned in person 2’s screen

If i understood your question correctly, these docs here are exactly what you are looking for.
Variables Blocks - Thunkable Docs
Check the “cloud variable”, it should help you achieving your goal.

As alternative, you can check the airtable’s component here, bit more complex but also more fun.

Hope it helps