How to disable auto-update function of apps?

Set up for all apps
1. Open "Play Store". Tap upper-left icon and then tap "Settings".
   


2. Tap "Auto-update apps" and then select "Do not auto-update apps".
   



Set up for individual app
1. Open "Play Store". Tap upper-left icon and then tap "My apps".
   


2. Select an app (here we take Calculator for example). Tap upper-right icon and disable "Auto-update".