As well as choosing the right size envelope, it is important to choose the right closure type for your requirements.
Gummed envelopes require you to apply moisture in order for the glue to become tacky and seal the envelopes. These are the most common sealing method and is also known as 'lick and stick'
Self seal envelopes come with 2 pre-gummed flaps and just require you to press the along the flaps to seal the envelope. This type of envelope has a short shelf life and are good for people who have a high use of envelopes.
Peel and Seal
Peel and seal envelopes are pre-gummed on 1 flap however this is covered with a removable strip. Once this strip is removed, simply press along the flap to seal the envelope. These envelopes have a longer shelf life however can be a bit fiddly when used in high post traffic environments.