Samples of invitation wording are found on websites like InvitationConsultants.com, which list a wide range of invitation examples for occasions like birthdays, weddings and funerals. They list several examples per category, for those looking for a specific type of invitation sample.
Invitation Consultants, a company still offering their services as of 2015, primarily lists samples of invitations in the form of fully-formed invitations. They list such a wide range that it is likely that any interested party visiting their website will find an example they are looking for. However, because they are a service that sells printed invitations to interested customers, they do not explain the entire process behind how to write an invitation.
Expressionery.com, as of 2015, lists an article that provides an explanation of how to appropriately word an invitation. It helps to piece together how an invitation is structured and all of the information required to make one, such as dates and gift rules. It lists basic examples, but does not offer as many as Invitation Consultants.
Many websites that offer samples of invitations are managed by companies that sell printed invitations as a service to people looking to invite others to their special occasion. Browsing websites like this is a good way to find ideas on how to format an invitation, as they often list examples of different types of invitations.