I worked for many years in an admissions office, so I took for granted that applicants understood what happens after they hit the submit button on their application. Sometimes, students panic because they log in the day after submission and notice that their application is marked "incomplete." I need to remind them that despite all of the technological advances we have, there are still humans involved in this process and some of the work is actually manual. So, here is a bit of a primer on what happens in the admissions office after you submit your application:
Once an application is submitted through Common App, a student will get an email with instructions to log in to the college/university's website - this is where you will track your application status. The problem is that students log in to this website immediately after application submission and panic because it looks like their application is incomplete. A person in the admissions office has to confirm that all of your application requirements have been received and then your status will be updated in their portal.
While you are responsible for submitting your application, your high school is responsible for sending your transcripts and, potentially, your letters of recommendation. While it is possible to invite recommenders to submit through Common App, most high schools use their college platforms (like SchooLinks, Naviance, Maia Learning) to submit teacher and counselor letters of recommendation. You have to rely on the high school to do this for you.
If a college requires official test scores, those need to be sent from College Board (SAT) or ACT. Someone in the admissions office may have to confirm that your scores are in their system and match them up with your application. The college/university websites will indicate whether they accept self-reported test scores for application review or require the official test scores to be sent from the testing agency.
Advice: when you see that an application deadline is November 1, you should request your recommendation letters WELL in advance of that date and order your required test scores to be sent to the schools that need them well in advance of that date as well. It can take two weeks or longer to send test scores to the college once you request them. You will notice that some colleges publish two dates - an application deadline and a materials deadline. This is because they know that not every student will have a completed application by the deadline and it gives the high schools a bit of wiggle room to submit the transcripts and rec letters. Your job as an applicant is to make sure that you have done everything in your control to get your materials to the school before the posted deadline.