In Toad, you can use
edit tablename where ...
and then simply edit the data in DB. Is there any equivalent in Oracle SQL developer?
No, but you can double click on the table name and and then edit it
Note: you should also be able to edit the data from the data grid shown in the SQL Worksheet but I haven't confirmed that
Ctrl + Mouse hover over the table or view name, that will open up Table Editor and you can edit the field values.