Set and adjust your CPA goal
Consider how much you want to spend on a conversion
You have the option to set a cost-per-acquisition (CPA) goal at the ad group level in your search results campaigns. Your CPA goal is the amount you ideally want to pay for a conversion. If you decide to set a CPA goal, it’ll be taken into account when determining what bid amount is used (up to your max CPT bid). Consider giving your campaign time to run so you can learn from the results before you set a goal. Note that your CPA goal isn’t guaranteed.
Once set, you can adjust your CPA goal at any time. If your impressions are low, you might want to consider increasing your CPA goal. For example, if your CPA goal is set lower than your max CPT bid, it can prevent your ad from being entered into auctions and limit the number of impressions and taps it receives.