Attach .csv Files to Report Subscriptions (Beta)
How: In Setup, from Reports and Dashboards Settings, select Let users attach reports as files to report subscription emails in Lightning Experience, and save your changes.
To attach files to a report subscription, subscribe to a report, click Attach File, choose Details Only. The attachment format is Comma Delimited .csv by default. Optionally change encoding or keep the default, and save your changes. The edit subscription dialog shows that the subscription includes an attachment. Finish setting other subscription criteria, such as frequency, and click Save.