mat stepper custom icon edit
<mat-vertical-stepper>
<ng-template matStepperIcon="edit">
<mat-icon>insert_drive_file</mat-icon>
</ng-template>
<ng-template matStepperIcon="done">
<mat-icon>done_all</mat-icon>
</ng-template>
<!-- Custom icon with a context variable. -->
<ng-template matStepperIcon="number" let-index="index">
{{index + 10}}
</ng-template>
<!-- Stepper steps go here -->
</mat-vertical-stepper>