How To Automatically Group Emails With the Same Subject Together in Gmail (Conversation View)

Labels are for sorting emails. They are similar to folders; however, they have some different mechanics.

Create a new label to sort your emails.

Attach labels to one or more of your emails.

Automatically attach labels to outgoing or incoming emails.

Apply a label to an email while composing it.

Remove one label from one or more emails and add another.

Remove labels from your emails.

Make changes to labels.

Access and update all your labels.

Display or hide labels in third-party mailbox services where you check your mail using IMAP, like Outlook or Mac Mail.