How can i hidden or remove the line that under <a> tag using html and css ?

a {text-decoration: none;}

you can apply the text-decoration as none in styling for <a>

By applying following css to a tag:

<a style="text-decoration:none">Link</a>

you have to set text decoration property none using styling

<a>

you have to apply text-decoration none property in styling of <a>