AMP articles now support sharing of original URLs so that users have the ability to share an original link to the articles they find from Google Search results, as opposed to being limited to sharing the AMP URL only. The new changes comes as part of an update to the AMP feature within Google Search and are designed to allow users the opportunity to have something which has been highly requested since Google launched their Accelerated Mobile Pages platform back in 2015. Google does mention though that they while thy wanted to bring a feature to the table that users have been asking for, they also wanted to do so while ensuring they didn't take away from the speed and performance that AMP articles have come to provide. Essentially they just didn't want to compromise the speed as AMP articles tend to open extremely quickly thanks to their less resource intensive format.
While the feature is being added today it's likely that it may take a few days or more to roll out to all users across the various Android devices out there. To check and see if you have access to the original links from AMP articles, once you tap on an AMP article from the search results there will be an anchor button that now appears in the AMP header bar. That anchor button will bring up the original article link instead of the Google specific AMP URL, and from there sharing the link is simple as all you have to do is long press the link to share it with whatever app you choose.
For now, that's how you share original URLs, though Google will be making it even simpler as they're making continued changes and will eventually roll out the ability for the Google app's share button to share the original URL instead of the AMP URL. This is only applicable to the Android version of the Google app though as the iOS app already shares the original URL when tapping the share button. Google doesn't state when exactly they'll enable the share button functionality for original URLs, but they do state that it will hit Android device in the "coming weeks."