The Mail app uses what are called Conversations to group your emails together. This is handy when you and your recipient are emailing back and forth on the same subject because all of those communications will be in the same thread.
And you may do a few things with conversations in the Mail app like highlight, expand and collapse, or disable them all. If the conversations in the Mail app on Mac are new to you, here’s how to work with them.

View your conversations
Expanding your conversations is a little different depending on if you use the Columnlayout in the Mail appor not.
In Column layout, you’ll see anarrow on the leftof grouped conversations. Just click the arrow to expand the emails.

In the default layout, you’ll see anumber on the rightof the message group showing how many emails are in the conversation. Click that number to expand the emails.
In either layout, you’re able to also clickView>Expand All Conversationsfrom the menu bar.

Highlight conversations in Mail
For ongoing conversations, adding a highlight can make them stand out so you can spot them easier.
ClickView>Highlight Conversationsfrom the menu bar.
If you disable the conversation view, which we’ll show you later, and clickHighlight Conversations, you’ll see the other emails in the thread highlight when you select one of them.
You can select a different color for the highlight in this case by following these steps.

1)ClickMail>Preferencesfrom the menu bar.
2)Select theViewingtab.
3)UnderView conversations, click the highlight color forHighlight messages with color when not groupedand choose a color.
Exclude emails from other mailboxes in conversations
The Mail app will include all messages grouped in conversations regardless of which mailbox they reside in, but you can disable this if you like.
3)UnderView conversations, uncheck the box for Include related messages.
If you want to temporarily exclude related messages, you can do this as well. This will hide the messages until you quit the Mail app and reopen it.
Select the conversation and clickView>Hide Related Messagesfrom the menu bar.

Disable conversation grouping
If you find that you’re not fond of the conversation grouping, you can easily turn it off. ClickView>Organize by Conversationfrom the menu bar to uncheck and disable it.
Wrapping it up
Using the built-in conversation feature inthe Mail appcan be very helpful for keeping related emails together. But it’s not for everyone. What are your thoughts on conversations in Mail? Do you prefer them or plan to turn them off?