You can use target cost-per-acquisition (CPA) bidding to help:
get as many conversions as possible within your budget
get as many conversions as possible within a flexible budget range
get as many clicks as possible within your budget
generate more clicks than manual bidding would generate
Explanation:
If your main advertising goal is getting conversions (like sales, signups, or mobile app downloads), then Target CPA bidding can help automatically get more conversions for your budget. It can also help you get more sales while paying less for the clicks that lead to those purchases.
Read more here: https://support.google.com/Google Ads/answer/2390684?hl=en