@Bondrusiek
I solved that. Do this steps:
Select the "Projects" tab on the left.
In the left side panel, select the "Build Android APK" section.
Scroll down to the "Build Steps" section and find the "Packaging" step.
In the "Packaging" section, you should see a "Sign package" checkbox. Make sure it's checked.
Configure "Signing Configuration" with required information such as keystore file path, keystore password, key alias and key password. If you don't already have a keystore file, you can create one using the java keytool.
Click the "Apply" button to save your changes.
Now try building your Android APK again by clicking on the green arrow icon (or using Ctrl + B) in the lower left corner of Qt Creator.
