While you can take screenshots on stock Android, the feature has been implemented in a bare bone manner by Google. On devices from Samsung and almost every other OEM, you can annotate and edit screenshots after taking them. Even Apple got around to adding the ability to edit and annotate screenshots with iOS 11.
However, on stock Android, Google does not offer any such feature. At best, you can quickly share a screenshot or delete it but even that’s only possible from the notification shade.
Google did start testing the ability to edit screenshots taken in the Google app last year but never rolled it out to everyone. Now, after plenty of tweaks, Google has started rolling out the feature to everyone with v7.21 of the app. If you are already on the latest beta of the app, make sure to enable the Edit and share screenshots option from Settings under Accounts and Privacy.
Once enabled, any screenshot that you take in the Google app will be followed up with a panel containing the Share and edit option. Tapping on edit will open a basic editor which will allow you to crop the screenshot and doodle on it.
Ideally, this feature should be available throughout the OS but that’s unlikely to happen until Google gets around to releasing Android P later this year. Until then at least, you enjoy the ability to edit screenshots taken within the Google app.
Knowing Google, the roll out of the latest version of Google app will take at least a couple of weeks to complete.