Yes, an Instructor can require Learners to submit a video and a text document to the Challenge stage of the Exercise.
Text documents cannot be submitted as standalone documents. In other words, all Exercises require a video upload. Additionally, a video must be uploaded first, before the Learner uploads a document. This article describes how a learner should submit a document.
If you would like Learners to submit text documents, please follow the below steps:
1) Visit your Exercise
2) Go to your Exercise's edit page (select Admin and then select Edit Exercise).
3) Under the Challenge stage, select Yes when asked if you want to require file uploads.