In fighting games, Character Select, also called Character Select Screen or just Select Screen, is the feature where players decide which fighting character they will pick for battle.
In the Street Fighter series, somewhat ironically, the character select screen had debuted in the second game, as the first one simply had Ryu and Ken, and the position of player decided which character would be played. The character select screen usually has the following elements:
An arrow or another visual marker to show which character has been highlighted.
Artwork of the character to further indicate who has been highlighted.
The name of the highlighted character.
Stats of the highlighted character, which would include items such as weight, height, difficulty, individual stats, among other things.
In older games, characters would simply be represented by a picture and the announcer wouldn't say their names. In more modern games, the character model is used to visualize them. When the character model is selected, they usually either say something or pose. For example, in Super Gem Fighter Mini Mix, Ryu crosses his arms, while in Street Fighter X Tekken, Dhalsim says "Allow me to show you the wonders of yoga", and in Street Fighter V, M. Bison laughs and says "Very good".
Extra Options
Some games ask for extra options to be selected. In all game modes of Street Fighter V,the game will ask for what V-Trigger is desired from the player. In Street Fighter X Tekken the game will ask how much health the player wants to start off within local vs in terms of total health (for example, Ibuki and Ling Xiaoyu have a below average max of 900 while Zangief has an above average total max of 1100, so picking 100% for Ibuki would mean she has 900 and Zangief would have 1100 and lower percentages will be scaled from their top health values so for example, if 75% health is chosen for Ibuki, it would be 75% of 900 and in Zangief's case, it would be 75% of 1100) and what Gem Units from a preset of 5 (as of the latest patch) the player desires to use.
Hidden Options
Some games (primarily the Alpha series) were infamous of keeping secrets from within the character selection screen. Alpha 2 Gold, for example, allows the player to select Cammy from M. Bison's character slot despite, Cammy being an altogether different character with a different fighting style and being hidden from the normal selection of characters. Other games need sequences of buttons, such as Super Turbo for picking Akuma and others require the usage of the "random" character selection slot which usually takes the form of a question mark.
Downloadable Content
More recent games allow for downloadable content (DLC). In these games, the initial roster is released with missing characters that will be filled in due time as new characters are released. For example, DLC characters in Street Fighter V and SFXTK, are changed in orientation.
Trivia
In many character select screens, characters related to each other in any way are usually placed near each other (immediately left right up or down), except for enemies, who are usually (but not always) placed on the equivalent spot of the opposite side.
Shin Akuma appearing in Ultra Street Fighter II: The Final Challengers' character select screen despite not being selectable by normal means via his status as a hidden character (his character icon can not be seen compared to the other normal characters).
M. Bison appearing in Alpha's character select screen despite not being selectable by normal means via his status as a hidden character (his character icon can not be seen compared to the other normal characters).
Juli appearing in Alpha 3's character select screen despite not being selectable by normal means via her status as a hidden character in the original arcade version of said game (her character icon can not be seen compared to the other normal characters).
Juni appearing in Alpha 3's character select screen despite not being selectable by normal means via her status as a hidden character in the original arcade version of said game (her character icon can not be seen compared to the other normal characters).
Street Fighter Alpha 3 Upper's character select screen.
Street Fighter Alpha 3 MAX's character select screen.
Super Gem Fighter Mini Mix's character select screen (Japanese version).
Akuma appearing in Super Gem Fighter Mini Mix's character select screen despite not being selectable by normal means via his status as a hidden character (his character icon can not be seen compared to the other normal characters).
Dan appearing in Super Gem Fighter Mini Mix's character select screen despite not being selectable by normal means via his status as a hidden character (his character icon can not be seen compared to the other normal characters).
Akuma appearing in X-Men vs. Street Fighter's character select screen despite not being selectable by normal means via his status as a hidden character (his character icon can not be seen compared to the other normal characters).
The PC/Xbox 360 version of Street Fighter X Tekken's character select screen with all DLC characters purchased.
The PlayStation 3/Vita version of Street Fighter X Tekken's character select screen. This version is notable as it has five exclusive characters, which consists of Toro (seen in this pic), Kuro, Bad Box Art Mega Man, Pac-Man, and Cole MacGrath.