Making text box text print in the output?

There's an event of textbox called FocusLost:

You could add a local script inside of the textbox like so..

local textbox = script.Parent

textbox.FocusLost:Connect(function(bool)
    if not bool then return end
    print(textbox.Text)
end)

The boolean value represents whether they pressed enter or not, the script is setup to exit the function if the textbox was left in any method other than by the enter key (i.e. clicking outside of the textbox)

Its pretty easy just do:

local output = textbox.text
print(output)

But thats assuming you made a value called textbox.