Automated bidding = Google fixes your CPC according to your daily budget Manual bidding = You set your own CPC per keyword Hope that makes sense, DJ
Though a pretty basic question, I think it does matter which to use dependent on your level of experience with paid search and bidding. I have always chose to manage my bids myself, a control thing mostly, at least that is what my business partners would say! But managed can be good for certain niche's and if you have limited experience.
Automatic bidding getting you the most clicks possible within that budget. Manual bidding gives you control to set the maximum amount that you could pay for each click on your ads.
if you want to maximize the total number of clicks and don't have a lot of time to manage individual keywords then you should opt for automatic bidding. keep in mind that not all clicks are created equal. manual adjustment allows you to target your best performing keywords and devote a larger percentage of the ad budget.
manual cpc will be according to your budget if you will set it maximum then you will be on top 1 in adwords and when you give permission to Google set your cpc Google will change it every time according to competition