Express delivery; a postal service that delivers mail faster than regular mail (commonly used as 'send by express').
重要な書類は速達で送ってください。
Please send the important documents by express delivery.
この封筒に速達のシールを貼って郵便局へ持って行った。
I put an express sticker on this envelope and took it to the post office.
海外へは速達よりEMSのほうが早い場合がある。
For overseas, EMS can sometimes be faster than express mail.