How to put password on apk?

I want to modify an apk and put password to it before they can use or install the app.

I really have 0 knowledge when it comes to coding...

Is this possible?

Can someone help me on this matter?

If you have 0 coding knowledge, I don't think that there is any tool that can help you. Now, with some coding skills, there are two things you can do:

• If you have the app source code you can write an activity that ask you for a password in order to load the app main activity.
• If you don't have the app source code, with some smali coding skills, you can use apktool to disassemble your apk and then inject an activity that ask you for a password. This is MUCH HARDER compared to the 1st option.

Please remember that any local password check can be reverse engineered and bypassed.

Otherwise, as said by others, since apk files are just rar archives, you can use winrar to add a password, but I'm almost sure that the installation process will fail.