General Emergencies 112
Fire department 123
Some of the government-run public hospitals are generally not up to Western European standards. If you want to get treatment quickly and have a better chance of finding English-speaking doctors, check out some of the private hospitals in the area. This is a more expensive option, but you can get travel insurance that allows you to go to public hospitals.
Travel insurance isn't mandatory but recommended. Choose a plan that offers coverage for Covid-19 and unexpected quarantine.
*this information is taken from the official CDC website
Being up to date with routine vaccinations is all you need when traveling to Montenegro.