There are many facebook video downloaders in play store.We copy the post url and paste in these apps they download video. I want to create a clone of these apps.
We are certainly not going to discuss app piracy, but perhaps you do not use the word 'clone' in that sense. If you do not mean piracy, you'll have to first register as a member and engage with other developers here if you hope for technical advice from them. https://forums.androidcentral.com/showthread.php?t=409154