anirudh444 HI
1/ It's inheriting the font-family of H1 heading in template, which exact font you want to use for this slideshow text?
2/ It seems that the editor you're using stripped out the HTML tags - the span tag of icon - I just updated for you:
<a href="tel:+0000000" class="btn btn-primary"><span class="fa fa-phone"></span>+954 128 8000</a>
3/ Our demo site uses this font settings: