is it possible to sort TAGs for exampel a-z or z-a ?
Yes - if you are asking about sorting tags within a group as they appear on a topic.
Go to the Map Index tab and right click on the tag group name. You will then have the option to sort the tags A-Z or Z-A, and this will affect the order they appear on each topic (assuming you have allowed multiple tags to appear on the same topic).
Unfortunately there is no way to sort tags from different groups as they appear on the same topic. These will appear in the order the tag groups appear in the Map Index, which can't be sorted (there is workaround for this but it is tricky and time-consuming to do).