There are several places within the configuration settings in the HWeb products where you may place a check mark in a box to Require a Credit Card.  For example: 
Tools Configuration Fare & Services Services Tab. Scroll to the right several columns and you will see a heading: Always Require CC?.

Placing a check mark in this column, or others similar to it, require that valid credit card information be captured as part of the reservation process.  If checked, a reservation may not be saved, unless complete and valid credit card information is entered.

Placing a check mark in this column does not mean that the reservation must be paid by credit card . They actual payment method can be any one of several other payment types, depending on what you have configured.

Examples of other places where the Requrire CC? configuration may be found: