The Samsung Galaxy S4 manual is available for viewing online on the Samsung website. Either navigate to the Support section of the website, or perform a search for this device using the search box on the Samsung home page, and then click on Manuals.
On the Samsung home page, first click on the Manuals and Downloads link found under the Owners and Support link. This takes you to the Download Center page. On this page, click on Cell Phones under Mobile. Click on the Select a Product drop-down button, and choose your carrier. Finally, select the model number of your Galaxy S4. If you are unsure about where to locate your model number, you can refer to the image alongside that can help you identify the model number. Now the page shows your device. Clicking on the device takes you to the download link page for the manual. The manual is now available in PDF format. You can view it online, download it or have it sent to your email address.
Alternatively, enter "Galaxy S4" in the search box to view a list of Galaxy S4 devices. Search for your model, and click on it. This takes you to the detailed specifications page. Click on the Manual link available at the bottom left corner of the page. Doing so opens the manual in your browser.