You can choose how you’d like to show the categories in the submission form. Navigate to Tevolution >> General settings >> Submission page.
From here you can change the settings for Category Display. The following options are available.
Check box: This will show the categories in hierarchy. A check box will be shown against the category name. This option will allow the users to select more than one category for his submission.
Multi-select box: The multi-select box will show all the categories in a list form. With this, multiple categories can be selected at once.
Select box: The select box will also provide a list of all the categories. It allows the users to select one or many categories from it.

According to what kind of submission you want to accept from the users, you can select the category input fields.