Today I get registered with Digitalpoint Forums and cannot find the option that How to insert Signature in My Profile / Posts? Please help me in this regard. Thanks
You need to read the policies! If you go to your settings and click on Signature you can read what you need to do to get a signature. You must have 10 posts and must be a member for at least 10 days.
You need to have 10 posts and member for 7 days. Once, you complete this requirement, you can open this link to insert your signature.
Also... something related... Search engines are blocked from viewing your profile and only logged in users see your signature. This means a search engine will never see either.
First at all, you shall read the FAQ - http://forums.digitalpoint.com/faq.php?faq=signatures#faq_signature_requirements