1. The easiest way is to fold the top over.
2. If you choose to use adhesive tape on your bag, only use low tack painters tape, so as not to damage the surface of the bag when the tape is removed. Low tack painters tape is available at any hardware store.
3. Do not use standard packaging tape, the adhesive is too strong and could damage the surface of the bag when removed. However, this won’t change the functionality or strength of the bag in any way, only the appearance.