Manual Actions are penalties that Google & other search engines give overly spammy websites, by removing one or all of their pages.
Manual Actions are different from regular penalties that are distributed by the algorithm & are treated as more severe.
Webmasters should aim to avoid spammy practices to ensure that their site is never victim to a manual action.
How To Avoid Manual Actions By Search Engines
The best way to avoid manual actions is to abide by the best practices for SEO.
While this is not always possible, it is the best way to avoid having your site intentionally penalized.
Intentionally trying to manipulate the search engine’s index will result in a manual action, as well as security issues that may lead users to unsafe content.
What To Do If Search Engines Give Your Site A Manual Action Penalty
Google Search Console will alert webmasters if their site has a manual action penalty against it.
Webmasters can see the exact action that has been taken against them, which URLs are impacted & a description as to what is wrong with the content.
Once this has been reviewed, work to fix the issues & make your page abide by SEO best practices & are accessible to crawler bots.
After the updates have been confirmed, request a reconsideration review in order to be re-indexed.
Note that throughout the process Google will alert you via email as to what is happening & the status of all items.