How i use html tags in ts file ionic 4

i have to use html tag in a variable like
let test=“



let  test="<html><h1>Hello</h1><h2>Mr</h2></html>"

How i used this. please suggest me any soltion

Your question is not clear at all.
However, I believe that what you are looking for is this:

let test = "<h1>Hello<h1><h2>Mr<h2>";
<div [innerHtml]="test"></div>