hey all ,i need a best developer guide for create custom module or overwrite and predefine functions knowlege .
Since you posted this on the Magento 1.x forums, I guess that you are referring to a guide to create modules for Magento 1.
Here you can find the official extension developers guide for Magento 1 from Magento:
There are a lot of resources related to that topic, I suggest you to take a look at the official guide and then search specific content in Magento blogs.
If you really want to learn all the things there are off-course multiple ways.
One is to read the guides of magento and fool around for some time.
You could also take some online courses (ex. lydia and other company's offer great deals on that). There are also ALOT of tutorials for magento 1.x..
Just make sure you aren't fooling around in magento 1.x and are following a magento 2.x tutorial or whatsoever haha.
Magento is an excellent eCommerce web development platform and it is one of the popular content management systems. So, finding useful resources to learn Magento should be easy. You can also hire PHP web developer or go through the Magento documentation to get an understanding of how the platform works. To learn Magento web development from scratch, you can invest time in going through varied online resources to know what this platform is and how it works. If you are willing or start with Magento 1.x then there are many resources to do this and the official documentation can be helpful to get a lot of information.