You can offer deposits in one of two places:
Product pages: the deposit widget shows under the product price. Each product can have its own offer. Use this when different products need different deposits.
Cart page: the deposit choice shows in the cart and cart drawer, above the Checkout button. One deposit applies to the order. Use this when you want one deposit for the whole cart and nothing on your product pages.
Where to find it
Depositly → Purchase options → choose Product pages or Cart page at the top of the page.
When you create a cart offer, the offer's Where it applies → Assign to is set to Cart (whole order).
How to switch
Go to Purchase options.
Click Product pages or Cart page.
Confirm the switch.
Live offers on the other side are set to draft. Nothing is deleted, and you can switch back at any time. Orders already placed are not affected.
Good to know
Only one cart offer can be live at a time.
A cart offer can cover the whole order, or only selected products. If you pick products, the deposit shows in the cart only when one of them is added, and only those items take the deposit.
A cart offer is deposit only. For installments on the cart, use Split payments.
Quantity limits, the image badge and estimated delivery aren't available on cart offers, because there is no product page to show them on.
Shopify doesn't let apps add a deposit choice inside checkout itself. The cart page is the closest place.