Check for update from apk (btn in the apk or other way)

I have the simple android app. And for updating it i just upload apk with new versionCode in manifest file to google play. Is there a way to notify users if the new version is available or insert button “check for updates” to my app? Maybe there is a google play API method which returns a versionCode of the current apk or others ways to do it.
Is there a direct link to the updating my upp (like a button “Update” in Playlay Market app)?