There’s no set answer as to whether one can use I in essays, always check with the professor.

In our essay, while it’s fine to use it in a limited usage–without filtering everything through the self–the audience is often best engaged by moving toward a use of readers.  The latter gives us a recognition that, yes, there is in fact an audience out there.  Everyone has a limited point of view, so it can be a problem having too many sentences starting with I.  Even so, I work with many students who share their relevant experiences.  If we are writing an essay about war’s impacts and the soldier-student has been deployed six times from Ft. Drum, they are subject experts with credibility.  Blended with other voices, their views can be credibly powerful.