We advise everyone to hand cancel their invitations. Hand canceling is the process by which your invitations are handled by post office employees and will bypass the automated processing machines at the post office.
If you hand cancel your invitations, it helps to avoid damage and minimizes the amount of automated printing and stamping that the post office adds to your mailings. Request for your mail to be hand canceled at your post local office. This way, each stamp on your envelope is marked using a hand stamp as opposed to the machine.
Before you put any stamps on your invitations, create a mock-up with everything inside. Then, take it to your post office. They weigh it and deem your envelope too bulky to be canceled by the machine or not. Also, they tell you how much postage you need based on the weight.
Now that you’ve figured how much your invitation weights and if it requires hand canceling, purchase stamps that reach your necessary postage. Remember, hand-canceling requires an extra cost (about 20 cents), so if your envelopes need to be hand-canceled, that amount needs to be included in the postage.