center text in a html file

<tag class="" align='center'></tag>

To text align all yuo have to do this:
<style>
  .yournameforclass {
    background: #fff; //which does not have to be there
    text-align: center;
    width: 100%;  //all of this can be varied. Text align can be used in these forms: left, which is to the left, right, to the right of the screen
    height: 300px;
  }