I found one way to do it using regular button on the template.
import { Component, VERSION, ViewEncapsulation } from '@angular/core';
@Component({
selector: 'my-app',
encapsulation: ViewEncapsulation.None,
template: `
<quill-editor customToolbarPosition="bottom" [(ngModel)]="editorModel">
<div quill-editor-toolbar>
<span class="ql-formats">
<button
type="button"
style="border: 1px solid red; width: 50px;"
(click)="handler()"
>
BTN
</button>
</span>
</div>
</quill-editor>
<br/>
<div>
<label>text to insert into quill editor</label>
<br/>
<input type="text" [(ngModel)]="name"/>
</div>
`,
styleUrls: ['./app.component.css'],
})
export class AppComponent {
editorModel = '';
name;
handler() {
this.editorModel += this.name;
}
}
stackblitz