Take a plain piece of paper and place the letter, check, or whatever else you’re mailing in the middle. Fold the paper into three or four parts, depending on the size of the envelope.


A similar option is to place your content inside a greeting card and then place the card in the envelope., Security envelopes will have a lining substance that makes it more opaque. These envelopes usually have unique colored patterns.They can be found at any stationary store or office supply store and should only be a dollar or so more expensive than regular envelopes.
 Another simple way to prevent people from reading through the envelope is to use two. In addition to your regular envelope, get another one with slightly larger dimensions and place the first one inside of it.
Wrap the content in paper.
Use a security envelope.
Use two envelopes.
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