An overdraft is a type of credit (borrowing) facility.
Payment history is reported to credit bureaus on a regular basis, which have their own method for calculating scores.
Generally, the use of a credit facility can support a credit rating as it demonstrates a person's credit experience. However, if credit payments are late or missed, it may impair your credit score.
Kroo has partnered with TransUnion credit bureau - more information is available on their website.