You can do in your .ts:

  inputValue: string = '';
  inputStates: string[] = [];
  undoStats: number = 0;

  onChanges(change) {
    this.inputStates.push(change);
    this.undoStats = 0;
  }

  undo() {
    this.undoStats++;
    this.inputValue = this.inputStates[this.inputStates.length - (this.undoStats + 1)];
  }

  redo() {
    if (this.undoStats > 0) this.undoStats--;
    if (this.undoStats >= 0)
      this.inputValue = this.inputStates[this.inputStates.length - (this.undoStats + 1)];
  }

and in html:

<div>
  <input
    type="text"
    [(ngModel)]="inputValue"
    (ngModelChange)="onChanges($event)"
  />
  <br />
  <button (click)="undo()">Undo</button><button (click)="redo()">Redo</button>
</div>

You'll only need to find a point at which you'll clear this.inputStates (like onSubmit or something like that).

There is the functionality already present by the system in input. You can try out the control z button and control y button.

If you want to create your own by then you have to add the mapping of user input fields and values and listen to the undo and redo events and based on that do the undo and redo by going up and down the array