Extraction of journey data and related details from Salesforce Marketing Cloud and to store the extract journey data in a DE location within Salesforce Marketing Cloud.
Depending on the journey data you want, you can get it from the system Data Views - see links below. Build an automation to run daily with SQL Query activities to query the Data Views and overwrite or append the data to DEs. You'll probably want to set a data retention schedules on those DEs if you go with append.