[NumLock]

1.
Unit StrUtils
function AnsiContainsStr(const AText, ASubText: string): Boolean;
Description
AnsiContainsStr returns true if the string specified by ASubText appears as a substring of the string specified by AText. Comparison is performed case-sensitively.

AnsiContainsText - case-insensitive
AnsiContainsStr - case-sensitive

2.

Код:

type
  TForm1 = class(TForm)
    Memo1: TMemo;
...
var
  s: String;
begin
  s:='это фраза, с запятой';
  s:=StringReplace(s, ',', #13#10',', [rfReplaceAll, rfIgnoreCase]);
  s:=StringReplace(s, ' ', #13#10, [rfReplaceAll, rfIgnoreCase]);
  Memo1.Text:=s;
end;