The 'Church' is not a building, or an organisation per se, but the people of God. The visible Church is those who are identified as following Christ. However, not all are true followers. The invisible Church is all true followers, even if some aren't connected to the visible Church. The 'local church' is where believers serve and are served, where they worship and find fellowship. The 'Church' is both the New Testament people of God, and in a wider sense all redeemed people including those from the Old Testament era too - those who are in Christ. There is one body, one Spirit, one hope for the future, in Christ alone.

Watch: https://youtu.be/feG5MDPP3OM