How do i open a letter and reseal it?

To open a letter without damaging it, gently slide a thin blade, like a letter opener or a craft knife, along the seam of the envelope to separate the glue. Be careful to avoid tearing the paper. Once opened, you can reseal it by applying a light layer of glue or double-sided tape along the flap before pressing it down firmly. Alternatively, you can use a sticker or seal to hold it closed.