Adding a Marker by using a Macro

Much as the title suggests, is there a means to use a macro to add a token marker to a token?

I know it might sound a little farfetched but I was wondering if that was possible.

By token marker do you mean like a symbol such as a colored dot or silhouette fist? API tokenmod is your friend. 

TokenMod (and other API scripts) can do this.  Scripts are a Pro Subscriber feature however, and there's no way to change token or character sheet attributes with a regular (non-API) macro.

I can recommend getting a Pro subscription for the API because TokenMod, PowerCards, etc., make GMing much easier & consistent. I upgraded to Pro after running my 13th Age campaign with a Free account for a year. 

You just need one person at your table to have a pro subscription to gain access to the API features.  The person who is pro just needs to be the initial creator of the session you play within and then remember to always play as a player when they join the game.