How do I change my e-mail address

I am using the free eMclient and have an e-mail address change how do I do that?

The question is rather vague…does this help answer what you were (maybe) asking:

https://support.emclient.com/index.php?/Knowledgebase/Article/View/109/5/how-can-i-select-which-account-is-used-as-the-default

If not, there may be other items in the searchable knowledgebase that might help.