Just like any other type of design, there is a right or a wrong one; instead there can be an invitation letter that lacks information or one that does not match with the formality of the event. There is a guideline/standard for the designers to follow and create a custom invitation design that is informative, catchy and nice enough to gain people's hearts. A modern and well-designed invitation letter must follow some of these below guidelines in order to do so:

• The complete information of the event;
• A consistent form of main colors, pattern, layout, and mood throughout the design;
• The legible and appropriate fonts/typography;
• The right mood & tone of the design that matches with the formality of the event;
• The paper material (for the traditional invitation letter) or the choice of format/template (for an E-Invitation).
• The unique or signature style of the host of the event (if any).

Normally, some people will choose to buy an already-made wedding invitation letter format in a gift shop, but many others tend to prefer to have a designer make them custom-designed ones to make it more meaningful and memorable on the biggest day of their lives.