I want to insert my photo as background in my video which has white background I just recorded a video of myself talking with background as white screen.Now i want to add my photo in that video, so that the final output should be like myself talking in a video with my photo in the background, replacing my previous white background
To replace a white background with an image, you need to use a Luma Key.  A Luma Key is like a Chroma Key, except that instead of using a color value (such as green or blue, usually qualified also by a certain level of luma), you will use only a luma value (such as anything brighter than 200 IRE).

Most NLE software have both compositing and keying functionality.  But now that you know what the effect is called, you can research how to access that functionality in the software you are using (or will use).