When I will Register for a/c on cj.com at that time I will not fill website or u can say blank the textbox of website url? So now can I past the Affiliate Programs code in my site? Or do any official procedure?
If you do not post a website, it is unlikely you will be accepted by merchants. There are some that approve you automatically so it may not matter. I'm not even sure you can do the application without putting in at least one site.
Yes, you can reapply if you are disapproved at first. Some are very picky and won't take you unless you have significant CJ earnings already.