While AdWords and Google Analytics can be connected to setup auto-tagging, this is not possible in Facebook ads though.
Correctly setting up UTM tags on ad links in Facebok is obviously essential to finding out performance related details, once the traffic hits the website.
Let's use an example:
Your website is: www.example.com
Content: facebook_creative1 [ad content field can be used to differentiate ad creative/targeting details].
Using https://ga-dev-tools.appspot.com/campaign-url-builder/ , your UTM tagged link would become: http://www.example.com/?utm_source=facebook&utm_medium=cpv&utm_campaign=Yourcampaignname&utm_content=facebook_creative1
Notice that I choose a medium called 'cpv' instead of social. Doing this helps separate paid social from organic social. In GA > Admin > View Level > Channel settings, you can then setup a source/medium combination to identify paid social channel where source matches regex 'facebook|instagram|twitter' and medium matches regex 'cpv'.
Setting up this link in FB Power Editor requires separating the ad link and UTMs to correctly setup. Here's the screenshot of a sample ad.
The critical part is separating the ad link and parameters [such as UTMs]. If you read this link from Facebook https://business.facebook.com/business/help/1016122818401732 it mentions that Facebook will join the display link and parameters to create a UTM appended link.
In the link field, only www.example.com goes in. In the URL parameters field, utm_source=facebook&utm_medium=cpv&utm_campaign=Yourcampaignname&utm_content=facebook_creative1.
Facebook then appends the utms to create http://www.example.com/?utm_source=facebook&utm_medium=cpv&utm_campaign=Yourcampaignname&utm_content=facebook_creative1
Entering a UTM tagged link in the parameters field creates something like this as an ad url, causing GA to lose UTMs and more importantly, bucket this traffic not under paid social.