You can use Airtable's copy and paste functions (C and V) to duplicate or move data.
For more on Airtable's keyboard shortcuts, see this article.
For information on how to use copy and paste to move the contents of records, see this article.
For information on how to use copy and paste to append data to your tables from within Airtable, or from other spreadsheet programs, see this article.
For information on how to use copy and paste in linked record fields to create new records, see this article.