Catfish allows you to customise most text labels and content within each storefront.
Login as an administrator to the storefront that has content that requires adjustment.
Choose Configuration -> Languages
The whole storefront is driven by the content of the English language pack.
Click the View String Resources link to access all entries in this language pack.
Use the filter button at the top of the VALUE column. Search for content you have found on the storefront you wish to change.
Applying the filter will return all instances of the search term.
Use the RESOURCE NAME column to identify if this value is the correct instance (the resource name normally contains page names that the value appears on, and a little more info)
Click Edit, and adjust the VALUE column ONLY. Save the changes you make.
These changes should appear instantly on the site.
NB Do not change the RESOURCE NAME. This column is a system function and will stop your site loading correctly.
NB Payment services can be renamed but must be added specifically (otherwise they will use their default) walkthrough can be found here