Typically, students showcase their app to teachers/peers to make sure the app is accessible prior to posting the finished project.
We recommend that teachers develop a grading sheet for each scene in their app so that the students can walk through their app from the point-of-view of the teacher.
You can reference this example rubric for grading app projects.
Depending on where you plan to have the apps published (ie. to a local iOS device or App Store), students will need to teachers to be involved in the publishing process.
Unless the students are familiar with using Xcode, teachers will normally review student projects prior to publishing to a local device or the App Store.
Then, the teachers would work with students to export to Xcode if they plan to publish (Reference Lesson 8: Publishing and Exporting to Xcode).