When completing a Meeting Activity, at the bottom where you can Schedule Follow-up, would it be possible to add Email to the "Schedule Follow-Up Activity". Thanks.
Emails aren't usually editable so they might not make good scheduled activities. Two alternatives:
Use the scheduled reminders feature (https://docs.civicrm.org/user/en/latest/email/scheduled-reminders/) to remind somebody to send the email at the future time, or to actually send the email, depending on what you want.
Add a new activity type called something like "send an email", and schedule that as the followup instead, just as a visual note.