What is the Minimum font size for all mobile view?
There is no definite minimum it depends on the user. (especially if you are concerned with accessibility) Some users will need to increase the font size (and the size they increase to will depend on external environmental factors e.g. are they wearing their spectacles or not) So you should set a size and allow the user to change it up or down as they wish. Even better allow the user to set a size and remember it for their next use – they still might change it but it is more likely to be correct than any size the developer would choose. This is why you should use relative font size changes if more than one font size so use EM as the size as in NB4’s answer