Your project registration form must be accompanied by a project proposal document.
It is worth taking time to write a good thesis proposal, since this will help you to find a supervisor and examiner for your project, and allow your registration to be processed more quickly. Material from a well written project proposal can be reused in your project planning document, and possibly also in the opening chapter of your thesis.
If your project is to be carried out in a research group at the department or within a company then it is likely that you will have been given a description of the project from the teacher or from the supervisor at the company. That description is not a project proposal! A project proposal is a document written by you, possibly together with a supervisor at a company or a teacher in the department, that describes the project and also places the project in the context of your education within your study programme.
The main readers of your project proposal are:
Describe the problem that the project will address. Typically a project will address some need identified by a researcher or by a company. Describe the motivation for the project from the stakeholder's perspective, and indicate the "missing piece" that your project will provide. After reading this part of your project proposal, it should be possible for other students in the programme, or for a teacher in the programme, to start to formulate their own ideas about how the problem might be addressed, before reading anything in the proposal about the methods that you expect to use.
Indicate how you plan to address the problem (or "missing piece") that motivates the problem. You do not need to go into great detail or provide a timetable, since these details will usually follow later in the planning document once the project gets underway. However, you should give enough information to enable the Examiner and Supervisor to assess the proposal.
Connect the project to your own education. Mention the relevance of any courses studied in your Master's programme for this project. If you are a student at the University of Gothenburg and you are aiming for a particular specialisation, state this in your project proposal.
Read the syllabus for the project course and explain how the project will enable the learning outcomes for the project course to be achieved.
State whether you have discussed the project with anyone at the department and, in particular, state if anyone has already agreed to supervise or examine your project. If not, indicate who you think might be an appropriate Supervisor or Examiner, or indicate what expertise you think it is most important for your Supervisor or Examiner to have. We cannot guarantee that your wishes or preferences will be granted, but it will help the registration process if you can identify individuals, research groups or Divisions whose expertise fits with the area of the project.
Please also read Robert Feldt's rubric for assessing a project proposal. Your proposal should score at least "3" for all criteria.