Prior to 2014, location data could be manually entered into Google Ads (formerly AdWords) accounts via the Shared Library to power location extensions and location targeting.
In the new Google Ads experience, manually entered business locations data will no longer be available as of December 1, 2018. Once we transition your account to the new Google Ads experience, manually entered locations will be removed, and you will no longer be able to use this data for location extensions or location targeting.
If we use manually entered locations in your ads, the ad formats will no longer show your locations, potentially impacting your ad performance. If you use manually entered locations for targeting, their removal may result in changes to targeting behavior. For example, if your campaign is targeting specific US business locations that have been manually entered, your geotargeting scope may change to all of the US. This may impact your targeting and audience reach, in addition to your campaigns’ costs and performance.
To transition away from manually entered location data, we will review your account settings in the new Google Ads experience, and set up a link to the Google My Business (GMB) account(s) we manage or that matches your business and goals so that your location data in GMB can be used for location extensions and location targeting in Google Ads.
You can learn how to link your Google Ads account to your GMB account in this Help Center article. For additional details on setting up location targeting, visit this Help Center article.
Original Source: https://support.google.com/google-ads/answer/7189290 and https://support.google.com/google-ads/answer/1722043 and