Guidance needed for I-130 Question about previous US visits and visa class information

While filling out the I-130 form, we came across the question asking whether the beneficiary has ever been to the US.

My fiancé has visited me in the US on short trips from Canada, so we selected “Yes.” After that, the form asked for the passport number, which we entered. It then asks for the visa class used to enter the US.

Do we need to fill in the visa class section as well? We watched a detailed YouTube video explaining how to complete the I-130 form, and the person in the video mentioned leaving that section blank.

Could someone please guide us on the correct way to complete this part of the form? Thank you.