An indicator can be said to be expressed by applying a formula to the price and trading volume values.
Charts such as Heikin-Ashi, Renko, and Line Break are also indicators because they are charts created by applying formulas to price and volume values.
There are limits to conveying your thoughts to others without using indicators or chart tools.
If you properly understand the definition of indicators and use indicators that are right for you, you will definitely get good results.