Initially, I thought the cinema and theatre was the same thing but I looked up multiple websites but gave different answers. I hope all of you can provide me with the correct differences.
In British English, a cinema shows films, while a theatre is where plays are performed live.
Cinema is also the name of the art of filmmaking, while theatre can also refer to art of performing on stage.
It is very rare in British English to use "theatre" to refer to a cinema, although BFI Southbank was formerly called the National Film Theatre.
In BrE if you say you're going to the theatre, people will always assume you mean a theatre, not a cinema - unless perhaps you speak with an American accent.
In US English, “theater” can be a place to watch either live plays or movies, and without context there is no way to tell which is meant. The word “cinema” is not often used in US English, and pretty much only in formal contexts.
“theater” can also refer to the art of performing plays, sometimes including writing them, but it is not normally used for the art of making movies (or films). The words “cinema” and “cinematic” are used in connection with the art of creating films/movies, and the industry that produces and distributes them, and other related things.
"Movie" is the more casual term, and by far the more often used, but "film" is the more inclusive term, and includes short films that would not usually be called movies. It is often used in a more formal context. "Video" is now often used for any moving image displayed over a computer or digital device, or designed to be so displayed, especially a short one not suitable for commercial full-length release.
The other answers explain UK usage correctly, to the best of my understanding. I am not sure about usage in Indian English.