If you're looking for the short answer to "how to make a birth certificate", that would be: "don't". It's illegal and quite hard if you're not a professional, and by that I mean either working for birth registration or having a lot of experience with digital photo editing programs. However, if you're really interested in this matter, like almost anything these days, it can be done. The question is, how much time and/or money are you willing to invest into this. The two factors mentioned earlier are usually in inverse ratio to each other: if you've got the money, you can have it done quick and painless, if you don't, well, then you'll just have to do it yourself. And for most of us that may take a while...

The first question in how to make a birth certificate is most likely: why? So let's take a look at your possible motives:

1. You don't have a birth certificate and you would like to posses one for whatever reason. From here on we can go into two directions by answering to these questions: have you been born and do you live in a civilized part of the world, have you ever had any birth certificate at all?

a. If yes, then congratulations, you're problem could very likely be solved, even legally and with minimum fees and nerve cells paid to our modern world's bureaucracy. Just head to the town you were born and try a police station or hospital. There work the officials who would know where to guide you to the nearest Public Health Service or Register Office. From then on you would have to fill in some forms and wait till they issue you a new birth certificate. Nothing difficult.

b. If you reply "no" to the previous questions, though I'm not sure how you got to read and understand this, well then... The bad news is, we can't really help you, but the good one is: the birth certificate probably isn't that vital to you anyway, so chill out and be glad there's one more thing you don't have to stand in line for .

2. You have or had a birth certificate you just don't want to use that any more, and in your quest to a new identity you thought about faking one. Well, here you've got a lot of options you can choose from, but we have to warn you, it's against the law and you could be facing prosecution if caught. 

a. Your easiest way is if you know someone from the earlier mentioned government agencies and either pay them good or have something really big you're willing to blackmail them with. If this works, you'll get the full treatment because you will not only own a paper, but probably be in the official registry also without actually knowing the technicalities of how to make a birth certificate.

b. You can do this not so elegantly with corrupt officials or delinquents at large who might posses connections in this business or someone else's original birth certificate with the owner securely out of the way.

c. You can try your photoshopping skills or use the blackmail card again at someone who has any, and just scan someone's birth certificate, change the names and other details and print it again. Mind you, it's not easy, because the government usually makes sure its citizens are nice and countable.

d. Type into a search engine: how to make a birth certificate, find a site selling fake ones, buy one and hope they do the job.