Ephesians 1:1

"Paul, an apostle of Christ Jesus by the will of God, To the saints in Ephesus, the faithful in Christ Jesus:" NIV translation

Paul identifies himself in this opening to the letter. He says that he is an apostle and that it is because of God's will and not because of man's designation. There are many today that want to claim a title and even go so far as claiming to be an apostle but there are and were some specific requirements to being an apostle.  An apostle was one that received their commission to start churches directly from the lips of the Lord Jesus. Jesus originally chose twelve and, after Judas betrayed Him, Paul was commissioned to replace him.

Ephesians 1:2

"Grace and peace to you from God our Father and the Lord Jesus Christ." NIV translation

Paul continues the introduction with a traditional greeting. "Grace" was the traditional greeting of the Gentiles at this time and "Peace" was the traditional greeting of the Jews (this is also where the common greeting of Muslims comes from although it is impossible to have peace without Jesus).

Ephesians 1:3

"Praise be to the God and Father of our Lord Jesus Christ, who has blessed us in the heavenly realms with every spiritual blessing in Christ." NIV translation

Next, Paul gives God the praise because we have it all in Christ. We need nothing else to have the spiritual blessing of eternal life with God. This is a reminder that we don't contribute anything to our salvation as it is strictly through faith in the perfect sacrifice of Jesus. Later in the letter, Paul will explain that, because of our salvation, we will be different but he opens with this reminder.