In the Text Editor view, you can view and modify the code in a UI file (.ui.qml) or component file (.qml) that is generated when you create components in Form Editor or 3D Editor and specify their properties in Properties.
You can also view and modify other types of text files.
To open the search dialog in Text Editor, go to Edit > Find/Replace > Find/Replace. You can also select Ctrl + F.
You can use a subset of the functions available in the Edit mode:
Available under certain Qt licenses.
Find out more.