Learn Portuguese (Portugal): A sopa ferve na panela.

In Portuguese, the simple present tense is often used to describe actions happening right now, which naturally translates to the present continuous ("is doing") in English. While you could also say está a ferver (is boiling), simply saying ferve is very natural and common in Portugal.

Why is it na panela instead of em a panela?

In Portuguese, you cannot leave em (in/on/at) and a (the) as separate words. You must combine the preposition em with the feminine article a. Together, they form the mandatory contraction na (in the).

If I want to say that I am boiling the soup, do I still use the verb ferver?

Yes! Just like the English word "boil", ferver works both when something boils by itself (like the soup in this sentence) and when a person boils something. To say "I boil the soup", you would just conjugate it for yourself: Eu fervo a sopa.