A "viewing" means to have an open casket.
A "visitation" is when the body is laid out in the casket (which may be open or closed) before the service so that mourners may come to "visit."
A "wake" means the family is present at the visitation for friends to approach and speak to, and informally offer condolences in person.
A "wake service" is when the wake is more formal, usually with a structured service, and attendees must remain seated. This is whether the service is religious in nature, with an officiant speaking and praying, or with a lay group performing a ritualistic ceremony, such as the masons, or a sorority or fraternity.
A visitation offers a chance for people to "pay their final respects" to the deceased. Just as important, the visitation can be a time for mourners to meet and console each other in a more informal setting than at the funeral.
You can schedule a visitation for as little as half an hour on the day of the service, or it can last for several days before the service.
The visitation can be restricted to just close friends and family, or be open to the public. You can even have a combination of private and public hours.
Is there a special ceremony?
As part of the visitation, you can arrange a formal ceremony, an informal ceremony, or none at all. The formal ceremony might be a brief service with the saying of the rosary (for Catholics) or prayers for the dead led by a mourner, elder, deacon or member of the clergy. It may also be a lay service from an organization as described above.
Historically, though, a wake means the friends and family keeping watch by the body before it is safely buried, especially through the night. (Hence the term "wake.") In some cultures, there may be drinking, feasting and storytelling during the vigil. In present day, these activities have been curtailed to fit modern day practices, and laws and regulations forbiding some activities, though some families may still carry them out in the privacy of their own home. Therefore, the term "wake" is sometimes even used to describe a reception after the funeral or memorial service.
Generally, though, for those who are comfortable with it, an informal storytelling session can be a wonderful way to remember the person.
The stories don't all have to be solemn, nor do they all have to show the person as a saint. We often love people as much for their flaws as for their strengths.
Remember, too, that laughter is as much a sign of strong emotion as tears or anger.
And if the person had a good sense of humor, there are bound to be some funny stories.
This sharing can be a rich and powerful experience. You might even want to record this event to play it again later.