SAN FRANCISCO  Turning itself into a kind of electronic vanity publisher, Scribd, an Internet start-up here, will introduce on Monday a way for anyone to upload a document to the Web and charge for it.

The Scribd Web site is the most popular of several document-sharing sites that take a YouTube-like approach to text, letting people upload sample chapters of books, research reports, homework, recipes and the like. Users can read documents on the site, embed them in other sites and share links over social networks and e-mail.

In the new Scribd store, authors or publishers will be able to set their own price for their work and keep 80 percent of the revenue. They can also decide whether to encode their documents with security software that will prevent their texts from being downloaded or freely copied.

Authors can choose to publish their documents in unprotected PDFs, which would make them readable on the Amazon Kindle and most other mobile devices. Scribd also says it is readying an application for the iPhone from Apple and will introduce it next month.