If you need support to change the position of the button, feel free to contact us.
The button is not shown in the desired position or you want to change its position.
The "Customize" button is shown by default into the HTML form of the product page. But, you can change its position by using this line at any place of the product page liquid file:
To change the position and text of the button, edit the liquid section product-temperate file by adding this code as shown in the following image. You have to place the code in the position on where you want to show the button: