The subscription type I need doesn't exist: do I have to leave the student's profile to create it?
No. In Add a subscription (student's profile, Subscriptions block), tap Create a subscription type, under Save. The same "New subscription type" window as in Settings > School > Subscription types opens on top. After Save in that window, the type is added to the school's types and chosen in the form: tap Save to create the student's subscription.
Owner only, like subscription types themselves.
See also
Didn't find your answer?
Write to bonjour@martialnote.com from your account's address, saying which screen is involved and the message shown. Support is by email only, with no guaranteed response time. Never send information about your students.