Present perfect. This town is completely different. Everything HAS changed. This town is completely different. [description of the town in the present] Everything has changed. [description of changes in the indefinite past with a connection to the present] More information: https://www.ef.com/ca/english-resources/english-grammar/present-perfect/ [excerpt] The Present Perfect is used to describe .... [different scenarios] An action when the time is not important. [this scenario]

Has been changed

Don't

Thank you very much (Lewis and Jamie) but I think it should be passive because someone who made a change to everything!

has - was would be for currently happening past tense, everything was changing - is, is a state of being present tense, look everything is changing! - has been, don't need been here