<li><a href="{%url 'corebloc_app:service_type%} smm">Marketing & Management Services</a></li>
This is the HTML code, trying to pass the string "smm" to this:
path("services/<str:service_type>", views.service_type, name="service_type")
So that I could have a path "services/smm" on my address bar.
The url template tag should be:
<li><a href="{%url 'corebloc_app:service_type' smm %}">Marketing & Management Services</a></li>
so you include the smm in the {% url … %} template tag [Django-doc]. If you want to use smm as string, you use:
<li><a href="{%url 'corebloc_app:service_type' 'smm' %}">Marketing & Management Services</a></li>