This is the 323rd most frequent Hindi word.
रखकर
"Having kept" or "placing".
Here, "रखकर" implies performing the act of placing the book and then proceeding to a subsequent action.
किताब को मेज पर रखकर वह चाय बनाने चली गई।
Placing the book on the table, she went to make tea.
"रखकर" is used to indicate keeping something aside before engaging in a new activity.
पढ़ाई की सामग्री रखकर उसने खेल-कूद में भाग लिया।
After keeping his study materials aside, he participated in games.
In this sentence, "रखकर" connects the completion of placing items in the bag to the next action of closing the door.