VBAやVBScriptでよく書かれてる奴をOfficeスクリプトで。
function main(workbook: ExcelScript.Workbook) {
let sheets = workbook.getWorksheets();
for (let i = 0; i < sheets.length; i++) {
let sheet = sheets[i];
sheet.activate();
sheet.getRange("A1").select();
}
}