For a while now, the Google Playstore offers the possibility of automated update installation: As soon as a new version of an installed app becomes available, you can have it automatically pushed to your device. This is an optional feature, and several things need to be considered:
- do you want automated updates at all -- or do you prefer to first check what has changed?
- you can enable/disable this on a per-app-basis
- you can set a default to be applied to apps not-yet-installed
- you might want to restrict auto-updates to WiFi only, e.g. to save your data plan
If you have questions/issues with this auto-update feature, this is the right tag to use. Optionally, you might want to use the google-play-store tag to make clear you really mean this kind of auto-update.