Looking at the other answers there seems to be some confusion. Assuming that you are referring to the feminine hygiene products then either is fine, in Australia it would be more common to just say pads.

Napkin sounds old-fashioned. It would be understood, but I've never heard anyone use 'napkin' in this context. Sanitary pads is the more usual term, or sanitary towels in the UK. If it's clear what you are talking about, you just say 'pads' (US and UK) or 'liners' for the thinner type. We tend not to use the word 'sanitary' if we know what the context is. The word 'sanitary' itself is rather old-fashioned, which is explains why one of the (male) answerers here wasn't familiar with the terms you were using. In a supermarket or large store, the section where you'd find these products will be called 'Feminine Hygiene'. The section of a super

You can say both but there are probably some regional differences. In the UK, you could also say 'sanitary towel'. 'Sanitary napkin' would sound odd in the UK.

Again - a man, but they are the same thing. 'napkin' is slightly more formal and/or old-fashioned.

We usually say 'sanitary wipes', 'wet wipes' or just 'wipes'. If it's just a plain napkin, we may say 'napkin', 'tissue', 'toilet paper', 'kleenex', 'paper towel' etc. I'm not familiar with sanitary pads or sanitary napkins. Generally, when I hear the term 'sanitary' when referring to a wipe, I assume that it's wet. I do not know of any napkins or pads that are wet. When I hear those terms, I think of something that is dry. I am a guy, though, so I may not be best equipped to answer this question.