Your organization is using PayPal as your payment processor. When your constituents attempt to check out (register, donate), they are presented with two options: Check out with PayPal or pay with a credit card. Paying with a credit card requires that users signup up for a PayPal account. You would prefer that your constituents not need a PayPal account to make a transaction on your fundraising website.
Your constituents may place transactions via PayPal as a guest with no need to create a PayPal Account. See details on the PayPal website. Note that this feature is available to Premier and Business account holders only. Please contact PayPal directly with any questions.