寄(jì) - to send (by post), to mail in Mandarin

寄 (jì) means to send something by post: a letter, a parcel, a postcard. 我要寄一封信给她 (wǒ yào jì yì fēng xìn gěi tā), "I want to send her a letter", is the basic pattern: 寄 (jì) plus the item plus 给 (gěi) plus the recipient.

The direction can be marked the way many Chinese motion verbs are, with 来 (lái) or 去 (qù) tacked on. 寄来 (jì lái) means sent toward here, as in 这封信是从英国寄来的 (zhè fēng xìn shì cóng Yīngguó jì lái de), "this letter was sent from England" - the letter's journey ends at the speaker's location.

Do not confuse 寄 (jì) with 记 (jì), "to remember, to record" - same sound, same tone, different character and different job entirely. 寄 (jì) is about the post; 记 (jì) is about memory.