Our desire to give is rooted in the Truth that we are created in God's image and likeness, and part of God's nature is to give.
What is tithing?
Tithing is giving 10% of your earnings to the church as an act of worship and obedience to the Lord.
Under the Law believers were required to give tithes or face the consequences of breaking the Law. Now under grace we give our tithe in order to honor the Lord willingly and not from obligation.
What are offerings?
Offerings are gifts over and above the tithe that are made to the church, individuals or organizations as you feel led.
In the Old Testament these were called "free will offerings."