Using TOAD Schema Browser/Create Table I created a table which included an identity column. The column was also set up using the Create Table tool.
I then copied the table to Editor and tweaked some names as I intended to generate a second table. Unfortunately the editor was flagging the Identity syntax that Schema Browser created as you can see in the attached picture.
However, the syntax is be valid. It runs successfully if I use the Editor “Execute as a Script” drop-down to run it using SQL *Plus.