Differentiate Kleene Star Closure and PLUS?

Given Σ, then the Kleene Star Closure of the alphabet Σ, denoted by Σ*, is the collection of all strings defined over Σ, including Λ.
Plus Operation is same as Kleene Star Closure except that it does not generate Λ (null string), automatically.
You can use other symbol for alphabet but we are mostly use sigma symbol.