In education, we often talk about wanting the children to have "a sense of agency." This means that we want children to know that they have choice, free will, and the right to say yes or no. We also want children to play an active role in their own learning, and feel a strong sense of independence. All of this relates back to the idea of "agency." So, for example, children have agency in their learning if you let them choose their own partner, pick one of three activities (instead of choosing the activity for them), or when you let them speak openly about their feelings. Another example would be having agency in your work; for example, your boss tells you to prepare a presentation on a topic, but it's up to you how to present that topic. Teachers on italki would have a strong sense of agency in their work, because they get to decide their own working hours, set their own pay, and work wherever they want (provided they have internet and a headset). Some sentences using the word "agency" might be: "Through nature play, we hope that our children develop a strong sense of agency." "I wish I had more agency in my job." "It's important for our workers to have a strong sense of agency and be able to work independently." To be honest, I rarely hear or use this word "agency" outside of business or education, but I hope this was helpful for you. :-)

I think the phrase is equivalent of some of these: sense of meaning or sense of value. Although wikipedia says: The sense of agency (SA), or sense of control, is the subjective awareness of initiating, executing, and controlling one's own volitional actions in the world.