Instead of using a fixed string value in your function. create a property in your app and use that. you can then modify its value in another function, which will change the behaviour of the other function.
% under properties section
properties (Access = private)
myvalue = "Hello"; % default value.
end
% under functions section
function Button1Pushed(app, event)
app.EditField.Value = app.myvalue;
end
% Button pushed function: InverseButton
function Button2Pushed(app, event)
app.myvalue = "Goodbye" %change the default value
end
