There are several options to show your cards after a hand is over.
The menu:
Make sure that these options are not checked if you want to show your cards.
If you're using a mobile device you can adjust the muck options by following the steps below:
To use this feature while in a game, when you're dealt into a hand, press on either pocket card. This will mark the card(s) you want to show and they will overlap. When you are last required to take action and you want to fold, you can then select 'Fold Show' to show your folded hand to the table.
The option to actually show your winning hand will appear once the hand is over. The two options (You Won 'Don't Show Cards/Show Cards') will quickly appear on the screen and you need to select 'Show cards' to show them.
It will only be available for a moment before the system mucks the cards and deals the next hand. If you fail to choose either option, your hand will be mucked when the time runs out.