Are foreigners allowed in Korea?

Excuse me, I'm a tourist from abroad. I'm planning to visit Korea soon and I was wondering if foreigners are allowed to enter the country. I've heard some conflicting information online and I'm a bit confused. Could you please clarify the entry requirements for foreigners in Korea? Do I need a visa? And what are the general rules and regulations I should be aware of before traveling to Korea? Thank you for your help!