If your marketplace is relying on PayPal as the payment gateway, buyers can pay by credit card. The payment happens on a page managed by PayPal, and its layout changes according to PayPal's choices and settings.
By default, if the buyer and sellers are in the same country, PayPal will offer options to pay by credit card without creating a PayPal account. However, sometimes it can be mandatory for buyers to create a PayPal account.
That is something that can be disabled.
How to make the PayPal account creation optional for buyers
This is a setting that has to be reviewed by each provider using PayPal in your marketplace.
To disable the PayPal account creation for buyers, you should advise sellers to:
Log in to their PayPal account
Look for the "PayPal account optional" section
Check the "PayPal account optional" setting: it should be "On".
Change it if necessary, save.
Note that this will impact only transactions where buyers and sellers are in the same country.
How buyers can check out without a PayPal account if they are in a different country than the seller
Unfortunately, enforcing that check out isn't possible from the seller's PayPal account settings.
However, sellers can get that option enabled if they request it to PayPal's support.
There are some situations where PayPal won't allow payment without a PayPal account for the buyer. PayPal hasn't shared a full list but some situations:
mobile payment in some countries
settings from buyers
risks about the transaction
What about Stripe?
Stripe doesn't require anything from buyers except the payment details (credit card number, ...). The payment form is fully integrated into your marketplace and isn't controlled by Stripe.