Forms can be configured to be accessed only by certain users or user groups.
That can be configured by following steps:
Step 1. Open a template and navigate to Options tab → Submission Options → Restriction by Group
Step 2. Choose one or several groups, which members should be able to use the form and click Add
Step 3. Publish the template.
If user which opens a new form is member of the specified group - form will be opened and submission will work.
Otherwise, if user is not a member of the group, following error message appears