How to pass all checked checkbox values on Form Submit in angular 4/6/7

You could use Form and NgModel

<form #checkboxForm="ngForm" (submit)="editPartyRolesSubmit()">
    <div *ngFor="let item of PartyRoles">
        <label>
        <input type="checkbox" value="{{item.Id}}" [(ngModel)]="item.Checked" [name]="item.Name" [attr.disabled]="item.Id==1 ? true : null" />
        <span innerHTML="{{item.Name}}"></span>
    </label>
    </div>
    <input type="submit" value="Submit">
</form>

function can be

editPartyRolesSubmit() {
  console.log(this.PartyRoles);
}

You can use this:

<form (ngSubmit)="editPartyRolesSubmit()">
<div *ngFor="let item of PartyRoles; let i = index">
    <label>
    <input type="checkbox"
           [attr.checked]="item.Checked == true ? true : null"
           (change)="item.Checked = !item.Checked"
           [attr.disabled]="item.Id==1 ? true : null" />
    <span innerHTML="{{item.Name}}"></span>
   </label>
</div>
<button type="submit">Click</button>
</form>

Or:

<form (submit)="editPartyRolesSubmit()">
<div *ngFor="let item of PartyRoles">
    <label>
    <input type="checkbox" value="{{item.Id}}" [(ngModel)]="item.Checked" [name]="item.Name" [attr.disabled]="item.Id==1 ? true : null" />
    <span innerHTML="{{item.Name}}"></span>
</label>
</div>
<button type="submit">Click</button>
</form>