Check out example codes for "mat hint". It will help you in understanding the concepts better.

Code Example 1

<mat-form-field appearance="standard">
    <mat-label>Standard form field</mat-label>
    <input matInput placeholder="Placeholder">
    <mat-icon matSuffix>sentiment_very_satisfied</mat-icon>
    <mat-hint>Hint</mat-hint>
</mat-form-field>

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