New Post: How to add the accessed time of a website?

You cannot by default. There are no fields available for such detail.

There is the possiblity to add extra elements but that results in an invalid model. There are some posts on the forum explaining how to do that.

A better option is probably to specify the time information in the comment field and move that from halfway to the end:

<format>{%Author:0%.}{ %Title%.}{ <i>%InternetSiteTitle|ShortTitle%</i>}{ [%Medium%]}{. {%Month:s% {%Day%, }}%Year%;}{ %Edition%}{. Available at: %URL:l%}{. Accessed {%MonthAccessed:s% {%DayAccessed%, }}%YearAccessed%}{, %Comments%}.</format>