The Big 5 Criteria can help you evaluate your sources for credibility:
In general, websites are hosted in domains that tell you what type of site it is.
Commercial sites want to persuade you to buy something, and organizations may want to persuade you to see an issue from a particular viewpoint.
Useful information can be found on all kinds of sites, but you must consider carefully whether the source is useful for your purpose and for your audience.
Fact checking can help you verify the reliability of a source. The following sites may not have all the answers, but they can help you look into the sources for statements made in U.S. politics.