The main purpose of the Spanish Mission was to disseminate and expand the religious conversion in Catholic faith.
Step-by-step explanation:
They aimed at converting the mass population into Christianity and expand the influence of it's teachings. The mission also focused on integrating Indians into political and economical framework of the Florida's colonial system.
They had a vision of expanding their Hispanic culture and Christianity among indigenous people. It was supported by the Spanish colonial government which saw that the spreading influence can bring so much change and peace.