Dell user manuals are available from Dell Support. Owners who don't know the model number but are looking for a manual for the computers they're searching with can download and install a program to help them find it.
User guides are also locatable with a Service Tag or Express Service Code. These are found either on the back or bottom of the device. Dell provides a video with how to locate either of them. The user guide can also be manually found by selecting the product category and then the product line and the model. Warranty information, solutions to common problems and drivers can also be found in the manual.