You can send an email relating to a specific task for any of your transactions. This can be done from the Task Pipeline or the Tasks section in a property.
PRO TIP:
If you are sending the same type of email for a specific task, you can use triggers to your advantage. Follow along with this article to learn how to leverage triggers to automate your transactions: How To Send an Email Using Triggers in Task Templates.
Task Pipeline
From the Task Pipeline, find the task you need to send the email from and click on the envelope icon. This will open a side panel to the right where you can compose your email or apply an email template.
Property Tasks
When working from the Tasks page in a property, you can click on the envelope icon on the task you want to send the email for. Just like the Task Pipeline, clicking the envelope will open a side panel on the right where you can start your email.
To learn more about composing or scheduling an email, follow along with this article: Sending and Scheduling an Email.