Categories for blogs?
Ning To Jamroom
Yes, you can pre-set the categories.
The forms your members are using when they add a blog post are the "blog create" and "blog update" forms.
The 'blog_category' is currently defaulting to a 'select_and_text' type.
Use the Form Designer.....
Docs: "Using the Form Designer"
https://www.jamroom.net/the-jamroom-network/documentation/jamroom-admin-handbook/1275/using-the-form-designer
.... to change the type to a 'select' type and in the FIELD OPTIONS, enter the options you want to give them.
Then they will only be able to select from what you've provided.
(Make sure you update both the blog/create AND blog/update forms.)