Escort cards are the most common way of assigning guest to their tables. Although displayed in various, creative ways, the card is picked up by the guest upon entry into the reception. The escort card will have the guests name, table number (or name) and entree selection. And whenever possible, assign the each guest their own individual card.
Place cards are positioned at the guest's place setting. You might find it in front of their plate or charger; used as a napkin ring or attached to the wine glass. The information on a place card will be the guests name and entree selection, and should you have a smaller celebration or informal event, you can omit the guest's last name. Should you use a place card, your guests will need to know their table assignment upon entry and this is why you would still need to use an escort card or display board.
Now if you are against the expense of printing escort cards or place cards, assign your guests to tables in a spreadsheet and provide that information to your wedding planner and/or hostesses. Guests will need to see them personally as they entire the reception to learn of their table assignment. This idea will only work if you guests are being served the same meal.