Masters research proposals often go before field or subject committees, while MPhils and Ph Ds go before full research degree committees (or whatever carries out that function in your university) where they will be read carefully by internal and external readers and by the committee.
The issues you deal with in order to write the proposal will run throughout the research.
It is a stage and a substantial piece of work from which you will draw in the future.
The latter can ask some very helpful questions about questions, aims, methods, theoretical underpinning and that fundamental question - so what?
That is, what will this piece of research lead to or contribute to? When you embark on your proposal, you are expected to identify your main research questions and sub-questions, to clarify for yourself: Draw up notes towards your own draft proposal under the following (typical) headings.