How do you check mail storage capacity of Microsoft outlook?

To check the mail storage capacity in Microsoft Outlook, go to the "File" tab and select "Account Settings," then "Account Settings" again. Choose your email account and click on "Data Files." Here, you can see the size of your mailbox and the available storage. Additionally, you can check the overall size of your folders by right-clicking on your mailbox in the navigation pane and selecting "Properties," then clicking on "Folder Size."