Have you looked here:
https://developers.google.com/apps-script/reference/spreadsheet/sheet#copyTo(Spreadsheet)
copyTo(spreadsheet)
Copies the sheet to another spreadsheet. The destination spreadsheet can be the source. The new spreadsheet will have the name “Copy of [original spreadsheet name]”.
var source = SpreadsheetApp.getActiveSpreadsheet();
var sheet = source.getSheets()[0];
var destination = SpreadsheetApp.openById("ID_GOES HERE");
sheet.copyTo(destination);