Export to CSV is a premium feature providing users a way to easily download and analyze blockchain data. It is available for tabs on the address page including transactions, internal transactions, tokens, and logs.
You will find the Download CSV button under the list of entities related to the tab.
Note: under the Tokens tab, the list of token transfers will be exported.
After clicking the button you will be forwarded to a /csv-export page for a given address and given type of export (transactions, internal-transactions, token-transfers, logs).
It is possible to specify an arbitrary period for the data export. By default, the current period is the previous month. After completing the reCaptcha, the data for the chosen period should be exported.