if i want to clear cpt then can i prepare for the exam from self study or online study without taking couching or classes. and which webside

Self study is a good option provided you are able to understand the syllabus conceptually. I would suggest you to refer study material provided by the ICAI and don't keep anything optional. You may visit portals like feeleminds, CAclubindia, etc for getting your queries resolved. Go ahead with full