After students take the PSAT, colleges will start purchasing lists from the College Board. If your student used their hs email to register for the PSAT, they can go to the College Board website and edit their account and change email addresses. The deluge of emails from colleges starts off small but, by this time next year, your student’s in-box will be filled with so much college spam that will be overwhelming. Take a peek at the comments on the Parents of HS Class of 2023 thread.
My suggestion:
Create a new email address for College Board and/or ACT. Make it something clean and simple (ex. Bob.Smith @ gmail). Use that email to register for college tours, to request info from colleges, etc.
Create a separate email address (ex. Bob_Smith @ gmail) that your student only uses on college applications. Emails sent to that address are important as the only entities that have it are the schools your student sent an application to. Information about setting up college portals, admissions decisions, housing, open houses, scholarships, etc. will be send to that email and won’t get lost in the masses of marketing emails that are sent to the college email account.