Blogger.com do not have any facility to provide or generate Contact form codes. Contact Form is important as it let's the visitors of your website to share their views and suggestions with the admin/author. There are some third party designers who helps you to get a Contact Form on your Blog.
The codes and instructions are given on their websites. You just need to create a account and login.
1. 123 Contact Form: http://www.123contactform.com/
2. FormSpring: https://www.formspring.com/
3. Kontactr: http://kontactr.com/
4. PagePow: www.pagepow.com/widgets/customize;contact
5. My Contact Form: http://mycontactform.com/
6. Email Me Form: http://emailmeform.com/