Go to ZBib.org.
In the "Cite" bar, enter either the URL for a web source, the ISBN of a book, the DOI or PMID number of an article, or the title of a source. (Numbers sometimes work better than titles.) If none of those work, you can click Manual Entry and fill in the blanks.
Your bibliography appears on the page as you add sources. Use the blue bar to choose your citation style.
Delete a source by mousing over it and clicking the X button that appears to the right.
To create an in-text citation or footnote, click the copy button to the right of the source and enter the page number you're citing. Then click Copy Citation and paste it into your document.
ZoteroBib stores your work in the browser on the computer you're currently using. If you clear your browser cache, it deletes the bibliography.
You can use the Link to This Version feature to create a version you can send to someone else.