Open Gmail in a web browser
Sign in to your account
Go to the Inbox or the folder you want to clear
Click the checkbox at the top left to select all visible emails
Click the “Select all conversations in this search” link if it appears
Click the “Mark as read” icon in the toolbar
Repeat for other folders or labels if needed
On mobile, open the Gmail app
Open the folder or label
Tap the sender avatar or press and hold an email to select messages
Select all available messages if the option appears
Tap the three-dot menu
Tap “Mark as read”