US universities ask for an official transcript. Can I send a notarised copy of my transcript? If yes, is it better to attest it by my university officials or notarise it?
When a US university asks for official transcripts, they are asking for transcripts to be sent directly from the institution at which the coursework was completed or the degree earned.
If your previous institution cannot send transcripts directly, find out from the US university what their specific requirements are. For example, see this FAQ from the University of Mississippi, which also describes how to get officially certified transcripts in case your institution cannot directly issue official transcripts.