When you archive a message in Gmail, it's removed from your inbox and transferred into the All Mail folder. To find an archived message, open the All Mail folder and use Gmail's search functionality to filter its contents. How you go about accessing the All Mail folder varies slightly depending on whether you're using the Gmail app for mobile devices or the Gmail website.
Find Archived Messages Using the Gmail App for Mobile Devices
Tap the three-line menu icon in the top-left corner of the Gmail app, scroll down if necessary and tap the All Mail button to display all of your messages, including those that have been archived.
Tap the Search icon in the top-right corner to begin searching for specific archived messages.
Enter your search terms in the Search Mail field and then tap the archived message you want to read on the list of search results.
Find Archived Messages Using the Gmail Website
Click the More button on the left of the screen to expand the main menu.
Click the All Mail button to display all of your messages, including those that have been archived.
Use the Search field at the top of the screen to search through your messages using names, keywords or email addresses. Click the Search button to filter your results and then click the archived message you want to read to view its contents.
Deleting and Restoring Archived Emails
Archived messages in your All Mail folder aren't stuck there indefinitely. You can either delete them or move them back to your inbox.
In the Gmail app, open the archived message, tap the three-dot More icon in the top-right corner of the window and select Move to Inbox on the drop-down menu to return the message to your inbox. Tap the Trash icon to send the message to the Trash.
On the Gmail website, select the archived message in the All Mail folder and click the Trash icon to send it to the Trash or the Move to Inbox button to send the message back to your inbox.
Items are stored in the Trash in Gmail for 30 days or until you manually delete them.