If you are using regular PayPal standard/business/premier (instead of PayPal Pro), buyers will only see a PayPal checkout button in their cart.
If the buyer goes to PayPal checkout and does not already have a PayPal account, then PayPal's site will usually offer a direct card-based checkout option without requiring a PayPal account, or the buyer can choose to create a PayPal account immediately.
If PayPal's site detects a cookie in the buyer's browser from a previous PayPal account login, then they will assume the buyer either already has a PayPal account or is using a shared/public computer, so they will not offer the direct card-checkout option in that case. If you are testing your own cart with a PayPal checkout, you would also encounter this behavior since presumably you would have logged into your own PayPal account recently; you should be able to see PayPal's card-checkout option by clearing your browser cookies before you test your cart.
PayPal Pro will not offer buyers a card-checkout option on PayPal's site after the buyer clicks the PayPal checkout button in their cart. Instead, buyers who wish to pay with a card would click the Pay With Credit Card checkout button in their cart, rather than clicking the PayPal checkout button.
