You can submit your application when ready, even if your recommenders have not completed and submitted letters of recommendation for you yet. Be sure to add the requests to your applications before you submit. That way when your recommenders complete the recommendations, the colleges will have access to them.
Before submitting your application, you must check the box affirming you understand you're responsible for making sure all required documents are submitted to the college.
See Add official documents to an application to learn how to add an official document to an application.