Multicamera television scripts (think: anything with a laugh track) have the most unique formatting elements of the common script variations.
Multicamera shows are shot on a stage in front of an audience, so their scripts look like a hybrid of screenplay format and play format. While each show has its unique variations, there are formatting elements that are standard.
In brief, some major differences:
Slugs/scene headings are often underlined. Sometimes, the names of each character featured in the scene are listed in parentheses directly below the scene heading.
All action and description is in all caps.
Character names are underlined the first time they are introduced.
Often, character entrances and exits are underlined. Sometimes, major physical transitions are as well, ie “JEFF CROSSES TO THE OTHER END OF THE ROOM.”
Major or important sounds, sound effects, and special effects are often underscored, and usually set off with a colon, ie “SOUND: DOOR SLAMS.”
Dialogue is often double spaced.
Parentheticals are more common than they are in feature screenplays. They do not have to be on separate lines, and are sometimes in line with the dialogue.
Often, scenes will be identified by a standard designation (ie “ACT 1 SCENE B”), and sometimes all new scenes will start on new pages.
The page header will often include the scene and act numbers below the page number.
Acts all begin on a new page, and start with the all-caps, centered act number written about 1/3 of the way down the page. For example, act two will start on a new page, with “ACT TWO” centered before the first scene header, and the top 1/3 of the page will be blank save the page header. This also applies to the cold open and the tag.
Acts end with a centered, all-caps “END OF ACT [NUMBER].” Again, this applies to the cold open and tag as well.
The end of the episode is indicated with an underlined, right justified “FADE OUT.”
To best understand multicamera script format, read as many as possible. This TV writing resource has some available to download under the US Comedy section. You will notice that most shows employ their own unique variations of the above rules.