@Christina-Sharon that is really an excellent question. One which many of us ask nowadays.
Here is a good answer, at least to the difference between the “visible church” and the “invisible church”.
A quote from the above link:
“Because not everyone who attends church or performs religious deeds is saved, the visible church includes unbelievers. The invisible church is comprised of the redeemed and sealed by God.”
That does NOT mean that all people who go to a church building are unbelievers. God’s chosen are in churches, not in churches, in every nation, tongue, and tribe around the globe. If you are saved by Jesus Christ and have repented of your sins, putting all your trust in Him, you are saved. If you are truly saved, you are born again. Your life has changed radically. If that has happened, you are one of the elect, or God’s chosen.
That said, fellowship is very important. But fellowship can and should happen both in the church and outside the church. It should be a regular thing too.
If you can go to church and the church you can get to is Biblically sound, then by all means, you should go. Take advantage of the rich teaching and good fellowship that grows out of that. But never ever mistake the sheep for the Shepherd. We are all sinners. But a truly Saved Christian cannot live in (wallow in) sin. There will be some who are not saved in the church. And there will be some who are saved outside the church. There are believers and non-believers both who do not attend church.
Church does not save us. Jesus Christ is the only Way, Truth and Life. We must all be saved and sanctified by Him. The way to do that (whether or not you attend church) is to read the Bible daily.
I am saying this because I spent the first 6 years of my Christianity doing mostly church and fellowship, but not enough Bible. It wasn’t enough to save me. The last 3 years of my Christianity have been rich and good because I have included reading God’s Word daily, to understand and learn who God is and hear what He says. He doesn’t “whisper” in our heads, He speaks in His Word: The Bible.
John 17:17 “Sanctify them with the Truth. Your Word is truth.” -Jesus praying for all people of all time that He has and will save, before Calvary.