I can´t do a fast text when i do a speedrun, cause i don´t know how to do, if anyone knows the trick or how to do, please tell me.

Maybe you're talking about the DIC basically is mapping the right/left keys to a single key of your game configuration, thats done because there's a delay before you can choose the option of something (ex. confirm grabbing something or selecting) if you read the guide of the next link you'll find more info.

http://www.speedrun.com/re3/guide/48r9l