Keywords, critical to your AdWords campaign are the keywords that you choose. Keywords are words or phrases you choose when you set up your AdWords campaign. A way to measure which keywords are good for your business is to carry out split testing. By matching your keywords with the ads you create, you make it possible for your ad to show when someone searches for similar terms, or visits a website with related content.
Your bid on keywords in the AdWords auction. AdWords determines which ads should show with a lightning fast ad auction, which takes place every time someone searches on Google or visits a site that shows AdWords ads. Your bid (1) The quality of your ad, (2) The expected impact from your ad extensions and other ad formats, Together these two factors determine when and if your ad will appear to potential customers.