Solitaire deals games in two ways:

Random Shuffle
A Random Deal shuffles the cards randomly and only some games can be won.

Winning Deal
A Winning Deal is guaranteed to have a solution which can be shown to you.

Tap the star in the toolbar for information about the game when a Winning Deal is being played. Use the slider to control the mix of Random and Winning deals.

A network connection is required for Winning Deals.