I checked my toddlers ipad browsing history and saw 100 of pages of porn! The only person who has access to it is my maid - what should I do?

Talk to her immediately and let her know the possible effects of her actions (not just for your family but for herself as well) if she still push through with watching porn. Because watching over hundred of pages of porn, most importantly if these pages have been watched for a very short period of time, can be a type of addiction already. Super agree with setting parental lock to restrict her access. You can also consider installing internet filter which blocks unwanted content.