In most no-limit hold’em tournaments or cash games, if players are following typically sound preflop strategy and are selective with their starting hand selection, the majority of hands will be heads-up after the flop. A player will raise, another will call, and often just two are still around in the hand to see those first three community cards.
As a result most no-limit hold’em strategy regarding postflop play tends to focus on heads-up situations, since they occur more frequently than do multi-way pots with three or more players still involved after the flop. But there are certain contexts where multi-way pots will occur more often, such as in lower-stakes cash games, daily tournaments with inexpensive buy-ins, or even in higher buy-in games where the table happens to have a lot of players playing passively preflop.