hey @Parinya_Rueangphun welcome to the Coda community!
I’m not sure what you’re trying to do … but generally you can’t rewrite the values of a canvas formula with a button. You could have the button change the value that the formula is referencing, but that isn’t “updating formula value”.
If you can explain a bit more what you are ultimately trying to do, we can probably find a way to do it!
If you make that a “control” instead of a “formula”, you can use a button to change the value. There are various types of controls from text box to select list drop downs.