Purely internet sources that have no printed equivalent can include:
The MLA template elements for web sources commonly include:
Complete website
Mikkelson, David. Snopes.com: Rumor Has It. Snopes Media Group, 1996-2016, www.snopes.com. Accessed 17 Oct. 2020.
Article from a news website
Tinker, Ben. "How to Make Better School Lunches." Turner Broadcasting, 23 Apr. 2015, www.cnn.com/2015/03/23/health/healthy-school-lunches/.
Article from a government website
U.S. Environmental Protection Agency, Climate Change, 17 Aug. 2021, www.epa.gov/climate-change. Accessed 1 Sept. 2021.
Blog post
Geist, Michael. "Pokémon Go Brings New ‘Augmented Reality’ Legal Issues to Light." CyberSmokeBlog, 20 July 2016, cybersmokeblog.blogspot.com/2016/07/by-michael-geist-yesterday-michael.html.
Tweet
For example
White House. "More than 30M Americans live in areas where there is no broadband infrastructure that provides minimally acceptable speeds." Twitter, 10 Aug. 2021, twitter.com/WhiteHouse/status/1425133446335238145?s=20.