FWIW is an abbreviation of For What It Worth. We often use it in online discussions, texts and e-mails as a way to introduce a comment or opinion that could be useful, informative or it could be merely an additional point of view. People also tend to use it to tone down advice or humility or tell them that what they are saying may not be of much importance but still it may be of use. It is informal, and has become commonly known in informal digital communication. Know more about fwiw meaning
(https://radarro.com/fwiw-meaning/)