Each Emacs frame always has a title, which appears in window decorations and icons as the name of the frame. The default title is of the form ‘invocation-name@machine’ (if there is only one frame) or shows the selected window’s buffer name (if there is more than one frame).
You can specify a non-default title for the initial Emacs frame with a command line option:
Specify title as the title for the initial Emacs frame.
The ‘--name’ option (see X Resources) also specifies the title for the initial Emacs frame.