In the form editor, click and hold a field to see placement options. To place it next to a field on a line, drag it to one of the available spaces on that line.
In the top right, click Publishto update your live form.
Please note:progressive profiling (Marketing HubProfessional or Enterprise only) cannot be applied to an individual form field in a row. When you make an individual field progressive, all other fields in the same row will automatically become progressive.