A string is a series of characters, such as "hello world." TIOS defines them within quotation marks (""). Built in, there are 10 string variables (Str0-Str9) that can be used by the user and by TI-Basic programs. Every character is valid to be entered into a string, excluding a quotation mark ("), a newline, and the /->/ symbol. It is, however, possible to get these characters into strings. String variables are accessed through the Vars menu, [2nd]+[Vars]+ will pull up a list of strings.
Storing to Strings
Strings are stored to like so: "Hello"/->/Str0 This will store the text "Hello" into Str0.