Question

Is this a run-on sentence?

Answer 1

Yes it is . Making a sentence with more than one subject makes it a run on . It’s easier to spot if you see that if has more than one coma it is usually a run on

Answer 2

Yes it is a run-on sentence

It's a combination of two sentences. It should be written as:

"Ms. Hartman, an interior designer, asks her clients to fill out a design questionnaire. She uses it to get a sense of their personalities and style preferences."