An Objective is somewhat controversial. I like to use one, but others claim it is obsolete. It is intended to be a brief description of what kind of job you're after. This is your chance to be picky about such things as company size, location, etc. If you do use one, it must be brief and meaningful. Keep it to two lines, maximum, and don't put in fluff. It should be about the job (short-term), not the career (long-term).
The problem is that if you write it too broadly, you will waste your time pursuing openings that turn out to be unsuitable, but if you write it too narrowly, you will not be considered for some openings that are suitable. It's a fine balance. If you don't think you can do it well, you may as well leave it off, so as to save space -- see the page on Resume English.
In addition to the usual "assumed subject I" rule of Resume English, the entire Objective is assumed to be the object of an assumed verb, something like "want", "am seeking", etc. For example, the sentence "I am looking for a neonatal nursing position in a large hospital in the southern USA" would translate into the Objective "Neonatal nursing position in large hospital in southern USA".
It may be also called a summary, if rephrased to include a little more about you, and may then be combined with material from a Skills Summary. For instance, my own resume currently uses a Summary that says: "Software engineer, skilled in wide variety of systems, languages, and fields, seeking challenging and varied position."