Hey,
Assuming the tables A and B are in different databases, you can use the below flow
copy activity>> on success>> Script activity
The copy activity would copy the data from table A to table B :
Reference: https://marlonribunal.com/copy-data-from-on-premise-sql-server-to-azure-database-using-azure-data-factory/
On successful execution of copy activity, use Lookup/SCript activity to update Table A
with below query:
update table A
Set temp.is_imported = 1
In case if the tables are in same database, you can create a stored procedure to hanlde everything