The phrase 'It's Signed, Sealed and Delivered' is a popular idiom that is used to express the idea of something being finalized or completed. The two crossword solutions for this phrase are MAIL (4 letters) and DEED (4 letters). MAIL refers to the physical act of sending something through the postal service, while DEED is a legal document that is signed and sealed to make it legally binding. Together, these two words represent the idea of something being finalized and delivered.