can I process salad dressing for shelf life in a water bath or pressure canner and if I can how long is the process time, I can't find out anything about it please help.
It REALLY depends on the recipe you are using. Lots of salad dressings contain either dairy or oil and neither of these can be safely waterbathed OR pressure canned.
Something like a seasoned vinegar might be okay though however I am unable to give advice on how to process that safely.
check http://nchfp.uga.edu/ for guidelines and safe processes and recipes (their search feature on their website is pretty good)