Can I limit the number of applications that a person can submit?

Settings > Registration > Registration limit for general settings and Settings > Categories for per category limit

In Settings > Registration > Registration limit you can choose to allow one application per registration, or multiple applications. If you choose multiple applications per registration, you have the option to set a maximum number of applications.

In addition, when creating your program categories in Settings > Categories, you can set the maximum number of applications that can be registered for each category.