What is the meaning of "length of notice"

You should always put your example within the context of a sentence so that we can clarify it's meaning.

please email your resume to my email address with expected salary and length of notice.

My best guess in that case is that the person wants to know how much time you'll need after being told you have the job to actually begin working.

Right. You have to "give notice" to your current employer that you are quitting your current job. Does your current employer expect to be notified one week in advance of your quitting? Two weeks? A month? This is the "length of notice".

CJ

thank you for helping me.