Gold is one of the 3 currencies used inside LoMM and can be earned and used in a variety of ways.
The main sources to get Gold is through battles in the World Map and your Gold Deposits. After winning certain battles they reward you a specific quantity of Gold and Crystals while the Gold Deposits in your Base generate Gold permanently, so be sure to check them often and collect the Gold before they reach their max capacity!
You can check the amount of Gold you currently have at the top right corner of the screen when you are at your Base.
After you collect the Gold you can use it in a variety of ways, the main one is to build new buildings and create materials. Gold is crucial for the development of your game because it is necessary for all the upgrades you need to do in your base in order to progress further in the world of LoMM.
Related buildings:
Gold Deposits - These are your gold mines, the more you upgrade them, the more Gold they generate for you, but remember whenever the deposits reach their max capacity they cannot produce more Gold until you collect what has already been produced! You can collect by tapping the deposits whenever the Gold icon is visible.
Gold Storehouses - This is where your Gold is stored after been collected, which means you have a limited capacity of how much Gold you can store before spending it. Upgrading your Storehouses increases the capacity that can be stored in each one of them.