When a hiring manager looks at your resume, she wants to see your skills and experience. But she also wants to see that you have a specific job in mind. That's what a "target job title" is. It's the job title you desire. When you put the job title on your resume, it helps speed the process of ensuring your resume gets to the right hiring manager. The job title should go immediately below your contact information on the resume.
What to Include
If you're sending a resume in response to a job posting, the job title should be the title named in the job posting. This can show that you are the right fit for the listed position. If you're not sure what the job title is, include a title that is somewhat broad but mentions specific industries, resume writer Beth Colley recommends on The Ladders website. For example, you might say you seek a sales manager position and then use a dash and include the industries you've worked in, such as "Sales Manager - Business Software." If you're a technical writer, mention what subjects you're skilled in, such as "Technical writer - IT, Finance." It's OK to mention two desired titles as long as they are related. Mentioning two titles that are not related will make you look like you lack focus in your job search.