You can use the Loco Translate to modify much of the text that appears in both the user-interface and the admin interface. To modify text from a plugin, navigate to Loco Translate >> and then select either Plugins or Themes. Then select the plugin or theme that you think is generating the text. Next search for the language you would like to edit. Finally, click the button "Edit".
The Loco Translate edit page displays all the text fields configured for the plugin or theme you are editing. You can use the Search function to locate a specific text field. To modify text, highlight the text you want to modify in the "Source text" area. Then, in the "Translation" area underneath, enter the new text you would like to appear.
In the example below, we are editing the US English file for the wp2print plugin. We are modifying the button text "Upload your own design" to be "Upload your files" instead:
