A friend (EU) has performed some freelance translation work for her former (Swiss) employer. Now they want her write an invoice for the service provided.

However, I believe it would be more advantageous for her to have the income taxed as part-time work (for the employer) at an hourly rate. (we don't know how self-employment is taxed and administered).

She is also currently looking for work, and (I believe) it would be beneficial to make social security contributions in a given month, so I think she should ask the employer to pay her wages, and make all the necessary deductions.

Any thoughts on the best way to declare / invoice freelance work (translation / teaching etc)?

Thanks