The Change History widget allows you to report on status changes for the account, ads, audience, budgets, keywords, network, placements, and targeting, on an individual basis.
Note: This widget only supports reporting on changes in Google Ads. The date ranges supported for this widget are within the last 30 days.
Setting it up
Under each change type category (for example, Account), you'll find the options to select (ad groups, campaigns, language, etc).
Regarding the date ranges, the data considered will be that of the last 30 days, however, if you select a range that is not supported (such as the last 90 days), you'll still be able to preview the information, but no data will actually be pulled.
This widget is also supported for Multi-Account reports, although please note that the data displayed will only be from Google Ads.
Previewing the Results
The "Modifications" column, as the name suggests, shows the count of individual modifications done to the "type" chosen.
For example, if you see '3' under the modifications column for 'type' Campaign, all '3' changes could be on a single campaign during the course of chosen date range, it does not necessarily mean that '3' different campaigns were modified.
If you choose the change type "Campaign" for example, those will include modifications done directly to the Campaign entity, and cover changes like Campaign Name changes, status changes, etc.
Any change inside the Campaign (for example, ad groups added/removed, keywords added removed, targeting added/removed) won't come under this selection.
Similarly, the Modifications columns for Change type as "Ad Group" will only report changes like the Name change, status changes done directly to the ad group.