When you select 'Continue on WhatsApp', your answers are used in your own browser to compose a message. Your phone's WhatsApp application then opens with that message already written. The website sends nothing to us, and nothing is stored anywhere on the website. You still need to press send in WhatsApp yourself before the school office receives anything.
If you instead select 'Open in email instead', your email application opens with a new message addressed to the school's official email address, with your answers in the body. Again, nothing is transmitted until you press send in your email app.
In both cases, the message then passes through WhatsApp or your email provider. Those companies have their own privacy policies and their own handling of your data — they are separate from this website and separate from the school.