Display entry category I know this is a really suck egg question, but I finding the Craft docs far less straightforward than EE (I'm just switching over), and so I'm struggling with the easy task of displaying an entry's category.
{% for entry in craft.entries.section('blog').limit(1) %}
   &lt;h2&gt;{{ entry.title }}&lt;/h2&gt;
                              
   
   {% if entry.byLine %}
   &lt;h3&gt;{{ entry.byLine }}&lt;/h3&gt;
   {% endif %}
                           
   &lt;h3&gt;Category: { ???? } &lt;/h3&gt;
   
   {% endfor %} 

Can anyone help?
To display a single category you'll need to do something like this:
{% set category = entry.categoryfieldhandle.one() %}
{{category.title}}

To display multiple categories:
{% set categories = entry.categoryfieldhandle.all() %}
{% for category in categories %}
{{category.title}}
{% endfor %}

Replace categoryfieldhandle with the handle you used for your field.
You can find more in depth and alternative ways in the docs:
https://craftcms.com/docs/3.x/relations.html
Since you're new to craft I recommend taking a look at the following course https://craftquest.io/courses/craft-cms-3-tutorials to help get you started.