Remove tags on single posts

What you want to remove in a single post is actually category of that post.
If you want to remove the categories under title in a the post, You can log in to Dashboard > Theme > Customize > General Settings,  add the following code to the “Header Script”

  <style>
 .single-post .post-categories {
     display: none;
 }
 </style>

 
– Not to display Tags in the left hand of the post, you can add the following code to the “Header Script”
 

 <style>
.single .tag-action {
     display: none;
}
 </style>

To change the categories in the single post of the DW Focus. You can add the following code to the “Header Code”

<style>
.single .site-content > .hentry .post-categories a {
    color: #FFF;
    font-size: 10px;
}

.single .site-content > .hentry .post-categories li {
     background: #...;
     margin: 0 3px 7px 0;
     padding: 0 10px;
}
</style>

Hope this helps !