Steps
(1) Download APK Edit Software from here. Download apk edit software
(2) Unzip the zip file and extract its contents. Click on "APK Edit.exe".
(3) First it will ask you to choose Java Executable from "Program Files" folder. Normally it resides in "C:\Program Files (x86)\Java\jdk1.6.0_25\bin". Folder may be different if you have different java version installed or different bits operating system.
(4) Later software will ask you to choose android apk file you want to edit. Browse the apk file you want to edit.
(5) Wait for some time until the Browse link becomes clickable in Details Tab.
(6) Now, click on browse and folder structure will be opened.
(7) You can make small changes like string name change, image change, app name change & save the file to reflect the changes in apk file.
To Change icon or images :- Replace existing images with new images.
To make string changes :- find strings.xml file in res and change the string’s values.
To make app name, package name changes :- Change the android manifest file.
After making all changes, save the file and close the folder structure. Click On Ok and you will see the android app with all the changes you made.
Source :- technonutty