First you should kblnow that what are these three modes of material actually. For this you have to read in context.
O mighty-armed Arjun, the material energy consists of three guṇas (modes)—sattva (goodness), rajas (passion), and tamas (ignorance). These modes bind the eternal soul to the perishable body.
So these three modes are actually three gunas of nature.
It is said the fruit of actions performed in the mode of goodness bestow pure results. Actions done in the mode of passion result in pain, while those performed in the mode of ignorance result in darkness.
You have a right to perform your prescribed duties, but you are not entitled to the fruits of your actions. Never consider yourself to be the cause of the results of your activities, nor be attached to inaction.
So these three modes (gunas) are based on our actions. These are the types of actions. In the verses 6-19 of chapter 14 it is defined that how they binds they soul. It did not mean that free will does not exist. By his will a person can even go beyond these modes.
Those who are alike in happiness and distress; who are established in the self; who look upon a clod, a stone, and a piece of gold as of equal value; who remain the same amidst pleasant and unpleasant events; who are intelligent; who accept both blame and praise with equanimity; who remain the same in honor and dishonor; who treat both friend and foe alike; and who have abandoned all enterprises – they are said to have risen above the three guṇas.**Those who serve me with unalloyed devotion rise **above the three modes of material nature and come to the level of Brahman.