Emails can be sent instantly or be scheduled to be sent at a later time/date. Emails can be sent from the Email marketing module or the Contacts/Participants module (depending on whether you are at Global level or Event level). Finally, it is also possible to set up automated emails, using the Workflows module. Please read our article about setting up automated emails to learn more.
From the Email marketing module:
Inside an email's detailed view, in the Participants tab, click on the Actions menu (3 dots) of the individuals you would like to send an email to and select Email.
In the popup window, select the Send email now or Schedule email.
Selecting Schedule email lets you choose the specific date and time at which you would like the email to be sent.
From the Contacts/Participants module:
Within the Contacts/Participants list, click on the Actions menu (3 dots) of the individuals you would like to send an email to and select Email.
In the popup window, select the Send email now or Schedule email.
Selecting Schedule email lets you choose the specific date and time at which you would like the email to be sent.