When you're citing web material, how can you be sure it won't be deleted or changed, or the link won't be broken?
It's a good practice to make sure that all URLs you've cited or referenced are saved using the Internet Archive's Wayback Machine.
You can navigate to archive.org, press on the "Web" menu at the top, and then add your URL and press "Save."
You'll then want to press the "save page" button on the next screen as well.
This may take a minute or two depending on the complexity of the page.
Once the process is finished, there will be a "visit page" link you can click on to check that all went well. The resource will be saved in a public collection, even if the live site is taken down or the URL changed.
Internet Archive Browser Extension
This can be made easier by using one of the Internet Archive's browser extensions or apps. These can be found at https://web.archive.org/.
As of March 2023, downloads are available for Chrome, Safari, Firefox, Edge, iOS, and Android.