I understood that people can make child styles for wordpress. But i wish to know are we able to create child plug ins. The reason behind this really is i wish to place some text or something like that towards the existing wordpress plugin without touching the wordpress plugin files. So my changes won't be affected while improving the wordpress plugin. Please advice it's possible or otherwise. Thanks

Use hooks &lifier filters to modifu your wordpress plugin function inside your styles function.php. Therefore It wont affect sometimes of up gradation.

Have look @ PluginAPI

there's no "child" wordpress plugin in wordpress... just produce a separate wordpress plugin to complete what you would like it to complete. It may sound like you should make use of a filter.