Your helper does not need to use your personal documents or signature to secure a loan. Documents typically required are copies of her employment contract (typically for proof of address - remember, this is her legal address that she can provide in Hong Kong), as well as copies of her visa and passport. She will usually be asked to list references and guarantors as well (usually other domestic workers). The loan will not be in the name of her employer and you have no legal obligation of paying it (unless you agree to sign as a guarantor, of course). She will also be asked for the landline number of her legal address, though the loan company would typically not call on this number unless she defaults on a payment.
If you are concerned that your helper might have loans, you can make sure she gets professional advice. Sponsor her to attend a confidential one-to-one financial counselling appointment with us to evaluate her finances and come up with possible solutions.