Junk or Spam folders primarily contain unsolicited, unwanted, or potentially harmful emails that have been automatically filtered out of the main inbox. 

Emails that have been successfully sent are stored in the Sent folder (or Sent Items folder). 

• The Outbox folder stores emails that are waiting to be sent. It acts as a temporary holding area for messages that have been composed and sent by the user but have not yet been transmitted by the email server. This folder is used to hold unsent messages due to connection issues or scheduled delivery.
• Outbox: Stores emails waiting to be sent.

• Bcc stands for Blind Carbon Copy.
• When a sender places an email address in the Bcc field, that recipient receives a copy of the email, but their identity remains hidden from all other recipients (including those in the To, Cc, and other Bcc recipients).

In Gmail, use the Reply all button to send your response to the original sender and everyone listed in the "To" and "Cc" lines. This option appears below the email message on both desktop and mobile app versions, ensuring all participants in the conversation receive the reply. 

You can flag (or star) an email if you want to remember it is important, and this also puts it in a folder (or a specialized view/label). Flagging serves as a visual reminder and acts as a tool to organize important messages for later, often aggregating them into a dedicated folder or list. 

Unfinished emails that are composed but not sent are stored in the Drafts folder. This folder acts as a temporary holding area, allowing users to save their progress, edit, and send the message later. 

The From field indicates the sender's email address. When you compose a message, this field is usually automatically populated by your email client with your own address to identify you as the source of the email. Standard email protocols (such as RFC 5322) require this field to be present in the email header.