URL parameters are used to track user behaviors on site (session IDs), traffic sources (referrer IDs) or to give users control over the content on the page (sorting and filtering). The issue with URL parameters is that Google sees each unique parameter value as a new URL hosting the same thing - meaning you could have a duplicate content problem. Sometimes, it’s able to recognize these URLs and group them together. It then algorithmically decides which URL is the best representation of the group and uses it to consolidate ranking signals and display in search results. You can help Google recognize the best URL by using the tag.
Use the URL Parameters Tool in Google Search Console to tell Google how your URL parameters affect page content and how to to crawl URLs with parameters. Use this tool very carefully - you can easily prevent Google from crawling pages you want indexed through overly restrictive crawling settings, especially if you have URLs with multiple parameters.