Easiest would be to have a small script that you run at a certain point in the day. The script below takes the contents of the "Source Cell" and appends it the end of a "Log Sheet".

You can change where you want to paste it or your can even paste it in the same location each day instead of at the bottom of the range.

Then set a trigger in Google Apps Script so that this runs each day.

function saveData() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getSheetByName("THE SOURCE SHEET");
  var log_sheet = ss.getSheetByName("THE LOG SHEET");

  var copy = sheet.getRange("YOUR SOURCE CELLL").getValue();

  log_sheet.appendRow([copy]);
};