i want to know which certification i have to do in salesforce,as of now i dont have any certificates.thanks in advance.As someone suggested me to take App Builder,but dumps are not availables.
As Ben said, it is a very good idea to look into the Beginner Admin track first. This is because even if you're a developer looking to transition to Apex, there are so many declarative features on the Salesforce platform that you can leverage to do things without code. And the Admin track will give you an insight into what is possible to do via code and what isn't. Also, you'll learn about the data object model, which will be so helpful to you.
For this, there is a lot of information on Trailhead you can learn.
More information on certs and good advice to follow can be found here, here and here. A relatively cheap way to learn the Admin track, other than Trailhead, is to check out this very comprehensive course here.
Salesforce has really become so broad now, and it continues to expand. So after you have taken the admin cert(s), you can then focus into an area which appeals most to you, be it Marketing or development or implementation etc.
Salesforce University continues to grow at a rapid pace, and the number of people who have certs and have Trailhead badges is increasing hugely. But it's really a combination of experience and certs which make you stand out and a smart way to get more experience is to volunteer your time via Catchafire and other websites.
Hope this helps.
If you go to http://certification.salesforce.com/ there is lots of good information about the certification program. I would suggest you start with the basic admin and then move to dev. ( but this really depends on what your focus is ) Admin is a good place to start as it will give you an overview of the platform and features. Good luck!
I definitely recommend this webpage http://www.sfdc99.com/, it also has tips&tricks to approve the most usual certifications.
Which one should you take depends on what are your role interests but I think for any developer admin & developer should be a must when you have some background on the salesforce developing world.