Wolfram: Show Function Help
Show Function Documentation in Notebook
Type
?FunctionName
in
Notebook
.
(* return help string of StringLength *) (* shortcut syntax *) ?StringLength (* FullForm syntax *) Information[ "StringLength" ]

Show Function Documentation in WolframScript
If you are runnig WolframScript in terminal, use:
?StringLength (* or *) TextForm[ ?StringLength ] (* StringLength["string"] gives the number of characters in a string. Attributes[StringLength]={Listable, Protected} *)
