Autosuggestion is a very powerful mental process. Everyone does it all the time. It is the term applied to all ideas, thoughts, proposals, or affirmations that are applied by yourself and that reach the mind through the five senses.

In the simplest language auto-suggestion is simply self suggestion or the process of making suggestions to yourself. They are the most dominant of your thoughts - the ones you dwell on, the ones that stay in the foreground of your mind - that reach the subconscious mind and influence it.Although most people are unaware of it, everyone has complete control over what messages get through to the subconscious mind. Even people who are aware of this principle seem to be unable to use it.

Subconscious Mind: Elsewhere on this site the nature of the subconscious mind has been discussed. The truth is that you are going to think and the nature of your thoughts will determine your outcomes.
If you don't take control and plant healthy positive thoughts in your subconscious mind with autosuggestion, you can be sure that your subconscious mind will accept the suggestions coming from other sources.
Your mind is like a garden. If you tend it and plant good useful seeds, you will reap a harvest of positivity in your life.

"Your ability to use the principle of autosuggestion will depend, very largely, upon your capacity to concentrate upon a given desire until that desire becomes a burning obsession." - Napoleon Hill.

Note: the app includes 70 Affirmations, 4 background sounds, and these binaural beats:

Binaural beats:

Gamma 40 Hz Higher mental activity, perception, problem solving.
Beta 20 Hz Active thinking and concentration." forState:UIControlStateNormal];
Alpha 10 Hz Relaxation, pre-sleep and pre-wake drowsiness.
Theta 5 Hz Meditation - Relaxation.
Delta 2.5 Hz Deep dreamless sleep, loss of body awareness.