Here is a list of functions from RTC, which you can use to work with local files:

// Does file with name “fname” exist?
function File_Exists(const fname:string):boolean;

// Size of the file with name “fname”
function File_Size(const fname:string):int64;

// Read “Size” bytes of file “fname”, starting at “Loc” (0=beginning)
function Read_File(const fname:string;
                           Loc,Size:int64):string; overload;

// Read complete file “fname”
function Read_File(const fname:string):string; overload;

{ Scan up to “Size” bytes of file “fname” for string “search_string”, starting at “Loc” (0=beginning), using up to “BufferSize” memory for scanning.   Larger buffer size will increase scanning speed, but also use more memory. Recommended is a “BufferSize” values of 16000 or more bytes. If “search_string” is found, its location in file is returned (0=beginning). If “search_string” is not found, this function returns -1. }
function Scan_File(const fname,
                          search_string:string;
                          BufferSize:integer;
                          Loc,Size:int64):int64;

// Delete file “fname”
procedure Delete_File(const fname:string);

// Write “Data” to file “fname” starting at “Loc” (0=beginning).
function Write_File(const fname:string;
                            const Data:string;
                            Loc:int64):boolean; overload;

// Write “Data” to file “fname”, overwriting old file.
function Write_File(const fname:string;
                           const Data:string):boolean; overload;

// File date and time
function File_Age(const fname:string):TDateTime;

// Get Temporary Directory path
function GetTempDirectory: String;

// Get Temporary File Name inside a Temporary Directory
function GetTempFile:string;