In this work, an exploratory study was carried out to analyze, through an anti-plagiarism program, the essays prepared by a group of postgraduate students. The focus of the study is quantitative, taking as a starting point the similarity index obtained with the iThenticate application, contrasting the essays in an artisanal way for an assessment of plagiarism. In a first analysis, a similarity index of textual copying of up to 90% was detected in some works, giving feedback to each student to correct their texts. Finally, the similarity index in the final delivery of the essays was on average 20.3%. In conclusion, using iThenticate allowed a rapid analysis of the essays, and that when collating manually, the plagiarism committed was evidenced; however, providing feedback to the student about the mistakes made was conducive to improving their writing and citation.