How do I get an apk file from an Android device?

md

step 1: Connect  Android device to pc
step 2: find package installed on device 
  + adb shell pm list packages -f -3
show list package for example:
  + package:/data/app/com.facebook.lite-8_89meYFwfdQ23e_DesbnA==/base.apk=com.facebook.lite
step 3: go to adb shell and pull apk file to sdcard
  + adb shell
  + cp /data/app/com.facebook.lite-8_89meYFwfdQ23e_DesbnA==/base.apk  /sdcard/facebook.apk
step 4: pull apk file to pc
  + adb pull /sdcard/facebook.apk <path_pc_pull_file>
ex:  adb pull /sdcard/facebook.apk Desktop