The signs demonstrate the power of the King. People were healed, some were delivered from demon possession. All these are included in the description “signs and wonders.” Christ promised this power to the church before he was taken up into heaven. His power as king in heaven was now being demonstrated by his messengers on earth. For references see footnote.1
13 Even Simon himself believed, and after being baptized he continued with Philip. And seeing signs and great miracles performed, he was amazed.