The latest version of OCS and OJS 2.4.8 and 3.1 support the use of the PayPal online payment system for secure online financial transactions. In OJS, this can be used to collect subscription fees, pay-per-view fees, membership fees, author submission fees, fast-track peer review fees, and donations. In OCS, this can also be used to collect registration fees.
This document will outline the basic steps in getting this up and running. You should, however, review the PayPal documentation to ensure that you have setup your PayPal profile to meet your specific requirements.