If you see a more serious change in your rankings e.g. going from page 1 to page 5 in 1-day or your domain name is completely removed from Google than you have a serious Google penalty and should contact a SEO expert for help and advice.
Penalties from Google can be from an algorithmic automated software filter that may even check different data bases that Google maintains about links and content. E.g. a duplicate content penalty, or the Google penalty might be a manual penalty given by a real human being (aka the Google SPAM Police). A manual penalty which generally requires writing to Google to understand what the penalty is and how you can fix it. You can contact Google from your "Google Search Console" if Google gives your website a manual penalty via https://www.google.com/webmasters/
Important Note: Many webmasters do not trust Google or the Google search console and if Google does give your website a fair or unfair penalty (Google mistake), you may not be happy with Google communications and you should have concerns about Google treating you fairly. Therefore you may be better off just ignoring Google, which means you will need to build a new website. You can still use your website that Google penalized, however it will not rank well in Google or it may be deleted from Google completely. I have personally seen Google make a mistake, then deny they made a mistake and refuse to fix it.
Thinking Google would never admit to or fix their defects and mistakes, then surprisingly sometimes (30% chance) Google will finally fix their mistakes, without admitting any wrong doing. This is why I generally advise business owners and webmasters to not trust Google and just ignore Google completely if possible when they unfairly penalize your website. However if your website did in fact violate Google guidelines, then you should fix the violation and submit to Google for reconsideration, then usually Google gives you a difficult time, and delays their responses. Finally after too long waiting Google will take the valid penalty off of your website.
Google may also send a message regarding your website. There are no "happy" messages that come from Google. Just a message about why Google penalized your website.
