Mail is a system in Genshin Impact where players can receive messages and attachments. All mail have a title, sender, message, time/date sent/received, attachments, and an expiry date of when it will be automatically deleted.
The Mailbox can be accessed from the Paimon Menu > Mail or by interacting with "A Messenger in the Summer Woods" in the Serenitea Pot. It has a maximum capacity of 1000. Once the number of Mail you have exceeds that number, the system will start to automatically delete Mail without attachments or Mail with attachments that have already been claimed in chronological order from oldest to newest. Additionally, the Mailbox display is limited, and will only display a portion of the Mail once it has gone over the limit. Delete excess Mail to display the remaining Mail.
The first attachment in the Mail is the item icon shown in the list of Mail.
All Mail can be claimed by selecting "Claim All" and all read Mail can be deleted by selecting "Delete Read".
Pinned mail cannot be deleted quickly and will be placed at the top of the mail list with a . However, they can still expire.
Mail that originates in the game will be in the language that the player has set the game to. Mail that originates outside of the game, such as from web events or the HoYoLAB Daily Check-In, will be in the language set there. The languages can be different for different sources at the same time.
No mail's language changes after receipt with the exception of the Traveler's Birthday Mail, which updates with any changes to the game language even after receipt.