What kinds of links to you mean? In your posts, or in your signature? If you mean that you are having trouble creating a signature, that's because you need to have been a member for 90 days before you can do that. Since you signed up in March, you aren't too far away.
Yes talking about Signature..i am not seeing edit signature in my profile so..
That's because you have not yet been a member for long enough. After you've been a member for 90 days (around 3 months) you'll see an area for adding/editing a signature. Some time in the next month you should be able to do that (depending on when you signed up.)
The reason for this is to discourage people from registering just so they can start to spread signature links everywhere. Anyhow, even when you can, the signature links are no-follow, so they are useless in terms of SEO. They are only of any use if you post regularly, so that other members see your links on a regular basis.