How do I edit text in photoshop cc after saving the file?

Hello

how do I change text after saving an image 

it may have already been flattened because I cannot edit it, I need to add 2 missing workd

Assumed your text is still text after saving (and not shapes or pixel or you does have flattened your image before saving).

Choose the text tool and click in your document between the letters.

If that does not work for you - show us a screenshot please with text tool active and the image and the layers panel with your text layer.

The very first question is do you have text on Type layer? Type layer thumbnail is marked in the Layers panel with letter T as on screenshot below.

If you have type layer then activate Horizontal Type Tool (my guess you have horizontal oriented text), navigate muse over text and click once, that will activate text so you can edit it. After editing text confirm using checkmark in the options bar or shortcut Ctrl + Enter. Another way is to select all text by double clicking on type layer thumbnail then retype text or click anywhere inside text then start typing or select only certain part of text to retype it/delete it.