Question

anybody can explain lac operan in easy way

Answer 1

It does this by binding to the operator, which partially overlaps with the promoter. When bound, the lac repressor gets in RNA polymerase's way and keeps it from transcribing

Answer 2

the lac operon is turned off. A repressor protein binds the operator (control) region upstream of the operon preventing transcription. When lactose is present outside the cell, it crosses the cell membrane and acts as an inducer of the operon. It does so once lactose is broken down to create allolactose.