There are 2 ways to reference in-text: Paraphrasing or direct quotes.
Paraphrasing is when you take another person's ideas, extract and summarise the important points and then making it clear from whom and where you have got the ideas you are discussing and what your point of view is.
For example: Fry, Ketteridge and Marshall (2015) argue that students who are active learners and take responsibility for their learning can challenge themselves.
Students who are active learners and take responsibility for their learning can challenge themselves (Fry, Ketteridge, & Marshall, 2015).
Fry, H., Ketteridge, S., & Marshall, S. (Eds.). (2015). A handbook for teaching and learning in higher education: Enhancing academic practice. New York: Routledge.