Paradise is a place of blessing where the righteous go after death. The word paradise is usually used as a synonym for “heaven” (Revelation 2:7).
When Jesus was dying on the cross and one of the thieves being crucified with Him asked Him for mercy, Jesus replied, “I tell you the truth, today you will be with me in paradise” (Luke 23:43). Jesus knew that His death was imminent and that He would soon be in heaven with His Father. Therefore, Jesus used “paradise” as a synonym for “heaven.” The apostle Paul wrote of someone (probably himself) who “was caught up to paradise” (2 Corinthians 12:3). In this context, paradise obviously refers to heaven.
There has always been a separation of believers and unbelievers after death (Luke 16:19-31). The righteous have always gone to paradise; the wicked have always gone to hell. For right now, both paradise and hell are “temporary holding places” until the day when Jesus Christ comes back to judge the world based on whether or not individuals have believed in Him. The first resurrection is of believers who will stand before the Judgment Seat of Christ to receive rewards based on meritorious service to Him. The second resurrection will be that of unbelievers who will stand before the Great White Throne Judgment of God. At that point, all will be sent to their eternal destination—the wicked to the lake of fire (Revelation 20:11-15), and the righteous to a new heaven and a new earth (Revelation 21—22).
There are cases in which paradise can refer to the Garden of Eden, such in the Douay-Rheims translation of Genesis 3:8, which speaks of Adam and Eve hiding “amidst the trees of paradise.” The context of the word will determine whether it refers to heaven or Eden.