Heaven is an actual place, in a real location, designed by God with people in mind.
Beings have traveled to and from heaven, including Christ (John 1:32; 6:33; Acts 1:2), angels (Matt. 28:2; Rev. 10:1), and humans (2 Cor. 12:2; Rev. 11:12).
Jesus, speaking as the bridegroom to his beloved bride, said to us, “I go to prepare a place for you, that where I am you may be also.” Heaven is that place.
The New Earth, where the heavenly city will be brought down to and relocated, will be a vastly improved form of the present earth and will have much in common with it—light, water, trees and fruit (Rev. 21:1-2), people and animals (Rev. 6:2-8; 19:11). The New Heavens and Earth is actually the eternal state, whereas the heaven we go to when we die is the intermediate state. So it is the New Heavens and Earth where we will live forever as resurrected children of God. It’s important to remember this, since people often think as if the heaven we go when we die is exactly where we’ll live forever. It isn’t. The return of Christ and the resurrection of believers is followed by the resurrection of the heavens and earth. That’s where we will live forever, as physical-spiritual beings in a physical-spiritual universe.
As a new car is a better version of an old car—but with the same essential components that make a car a car (four wheels, engine, transmission, steering wheel, etc.)—the New Earth will be a far better version of the old earth, with the same essential components. Heaven will exist in the realm of the New Earth and will therefore be very earthly in its properties. Since it is not only the dwelling place of God, but is fashioned by God to be populated by people, the present heaven is also people-friendly, designed with their God-given desires in mind. (No child can get excited about a heaven that isn’t physical.)
For more information on the subject of Heaven, see Randy Alcorn’s book Heaven.