You can set additional add to cart button options in Catalog Settings > Shopping Cart:
Button label
This is the button text. By default it id Add to Cart. You can customize the add to cart button label.
Button Description
The text that shows up under the add to cart button.
Cart added info
The box that shows up when the product is added.
Replace button with URL
This option will replace the button with simple link.
Redirect to cart after click
By default the product is added and the user stays on the same page. With this option selected the user will be redirected to cart after the product is added.
Disable Quantity box
This will disable the quantity box near the add to cart button.
Enable minimum quantity box
This will enable the minimum quantity option on the product edit screen. If a product has this number filled it will be impossible to buy fewer pieces than defined (in one order).
Enable maximum quantity box
This will enable the maximum quantity option on the product edit screen. If a product has this number filled it will be impossible to buy more pieces than defined (in one order).