Move or copy emails in Mail on Mac
You can move or copy email messages between mailboxes in the Mail sidebar or the Favorites bar.
Move emails
In the Mail app
on your Mac, select one or more messages.Do one of the following:
Drag the messages to a mailbox in the Mail sidebar or the Favorites bar.
Click the Move To button
in the Mail toolbar (you may need to first click the More Toolbar Items button 
), then choose a mailbox (or use the Touch Bar). Mail may suggest a mailbox based on where you’ve moved similar messages in the past.
If you move a message that’s part of a conversation to another mailbox, it becomes a related message, but is still shown in the conversation. See View email conversations.
Copy emails
In the Mail app
on your Mac, select one or more messages.Do one of the following:
Press and hold the Option key while you drag the messages to a mailbox in the Mail sidebar or the Favorites bar.
Control-click the messages, choose Copy To, then choose a mailbox.
If you have an IMAP account and are unable to move messages, it’s possible the messages contain invalid characters (typically added by a mail server) or are too large, or you exceeded the storage limits set by your email account provider.