-- this is only possible with the Branding free license (feature) --
You can change the title in the Translations (Merchant panel -> Configuration -> Language -> select language -> edit -> open Translation tab).Search for the string of "Post Affiliate Pro" . Search is case sensitive.
You can change the title for the merchant panel by editing this entry in the second (translation) column: %s - Merchant Panel - Post Affiliate Pro
title for affiliate panel by editing: %s - Affiliate Panel - Post Affiliate Pro .
title for affiliate signup: %s - Post Affiliate Pro
%s is the variable that shows the actual opened page (Home, Plugins, Transactions, Login... -> hese pages can be found and modified at Configuration > Affiliate panel > Menus & Screens)