How To Use Liquid Bubble Addon:

1. click on the bubble image to add bubble :

2. select from the scene collection select bubble to see the addon setting :

3. finally you just need to play with the setting to get what you want :

How to fix image render problem : 

you can fix that by : 

1. convert bubble to mesh :

2. delete the cube that exists in the Scene Collection :

that's all, I will try to fix this problem in the next update, If you want to render animation you will not face this problem :

How To Make 3D Abstract Bubbles Animation In Blender: