Get Report Details Emailed in .xlsx Format
Where: This change applies to Lightning Experience in Group, Essentials, Professional, Enterprise, Performance, Unlimited, and Developer editions.
How: On the Reports page, select the Export row-level action for the report. Click Details Only and then select .xlsx as the Format option.
If security is a concern, you can hide the .xls option by selecting Hide the option to export a report in XLS format in Lightning Experience in Reports and Dashboards Settings.