How to edit the default bid of one or more ad groups
- Sign in to your Google Ads account.
- Click Ad groups in the page menu.
- Check the checkbox next to any ad group with a default max. CPC that you’d like to edit.
- In the Edit drop-down menu that appears, click Change bids.
- Enter a new default max. …
- Click Apply.
For More Information Please Refer: https://support.google.com/google-ads/answer/2375408?hl=en