how to change Add to Cart button from square one or the rounded one like this?

[Senku]

how to change Add to Cart button from square one or the rounded one like this? i only want to change "Add to Cart" button. i prefer to use custom css

[BiDeal-Discount]

Hi,

please share your store url to let me check which class selector to CSS, normally you can use:

.add-to-cart {
  border-radius: 10px;
}

with .add-to-cart is your class selector

[Senku]

here it is: https://seasonalcollections.co/collections/all-products

your css didn't work

[BiDeal-Discount]

Thank you for provide site url, let try to add this css code:

button.product-form__submit, button.product-form__submit:before, button.product-form__submit:after {
  border-radius: 20px;
}

The result will be: