Yes. Paypal was activated in the Enrollment plugins, and "Allow Paypal" was set to "Yes" from the beginning. Those are familiar settings from earlier Moodles that had not been changed, so I know to use them.
What I cannot find anywhere is the Enrollment Methods page where I can open a particular course, then turn Paypal on for that course, then set the cost and other variables for that course.
As a standard test on a new Moodle installation, I always enroll a fake student account and pay through Paypal, to make sure it works. This time, it did not work.
After creating this student account, then clicking to enter the course and pay, I get the message "You cannot enroll yourself in this course."
HERE'S MORE: I can't even find where to enroll students in the course I created. The Enrollment Methods option in older Moodles contains the option for displaying enrolled students and adding new ones. I do not see that anywhere.
As a precaution, I gave myself additional permissions -- administrator, manager, and course creator -- just in case enrollment was limited to one of those roles. No improvement.