Even if you are employed in your home country, you will be covered by most labor rights in Denmark if they are more advantageous than your rights in your home country. This applies, among other things, to safety, minimum wage and working hours. This does not apply to termination of contracts and supplementary labor market pensions.

If you work as a posted worker in Denmark for less than six months, you normally do not have to pay income tax here. However, there is no general EU law that determines which country can collect tax on your income during a posting.

Your social insurance usually follows your tax payment, so make sure your employer actually pays your taxes.

Make sure you and your family are socially insured.

If you, as a posted worker, still want to be covered by the social security system in your home country, your employer must request a PD A1 form from the social security authorities of your home country and inform the authorities of the host country accordingly.

If your posting lasts longer than two years, you can either:

Switch to the social security system of the country where you are posted, or

Ask your employer to apply for an extension of your right to social security so that you remain covered in your home country.

Source: https://europa.eu/youreurope/citizens/work/work-abroad/posted-workers/index_en.htm

More information in english:

https://workplacedenmark.dk/en/regulations-on-posting/

https://workplacedenmark.dk/en/regulations-on-posting/your-rights-as-a-posted-worker/