By purchasing Org Chart for SharePoint SE/2019/2016/2013/2010 you get a perpetual license.
One license allows installation to two Web Front End servers (WFE). You need to purchase separate license for each two WFE servers you have.
Find more information about WFE servers in this article.
The license includes one year of updates and Standard Support Plan.
The license is perpetual, but you can renew it to get one more year of Standard Support Plan and updates.
You can purchase renewal from your shopper account.
The same applies to Development license, except it can be installed to development or testing servers only and you don’t need to renew maintenance.