If men and women have free wills and angels [holy & fallen] have free wills, for what purpose did God create mankind and for what purpose did God create angels?
The answer to one of your question can be found in a previous question, “Why did God create man?” Now, why did God create angels? Part of the answer is found in the following verse,
Are they not all ministering spirits, sent out to render service for the sake of those who will inherit salvation? (NASB) Heb. 1:14
This verse tells us that angels have the responsibility of taking care for Christians. Angels are also God’s servants to do whatever He wants. Here are some passages that reveal how angels serve God.
When the angel stretched out his hand toward Jerusalem to destroy it, the LORD relented from the calamity and said to the angel who destroyed the people, “It is enough! Now relax your hand!” And the angel of the LORD was by the threshing floor of Araunah the Jebusite. (NASB) 2 Sam. 24:16
And the man who was standing among the myrtle trees answered and said, “These are those whom the LORD has sent to patrol the earth.” So they answered the angel of the LORD who was standing among the myrtle trees and said, “We have patrolled the earth, and behold, all the earth is peaceful and quiet.” (NASB) Zech. 1:10-11
For the Son of Man is going to come in the glory of His Father with His angels, and WILL THEN REPAY EVERY MAN ACCORDING TO HIS DEEDS. (NASB) Matthew 16:27
Or do you think that I cannot appeal to My Father, and He will at once put at My disposal more than twelve legions of angels? (NASB) Matthew 26:53
The angel answered and said to him, “I am Gabriel, who stands in the presence of God, and I have been sent to speak to you and to bring you this good news.” (NASB) Luke 1:19
And immediately an angel of the Lord struck him because he did not give God the glory, and he was eaten by worms and died. (NASB) Acts 12:23
Angels serve God as messengers of information, warriors, destroyers, and protectors. Why does God use angels? We do not know. He simply chose to do so.
God created man for fellowship, and He created angels to assist Him in a variety of ways. One of the primary responsibilities of angels is to minister to Christians. Now that is very special. May the Lord bless you.
Reference Links:Angels - Good & Evil
Why did God create man?