Learn Spanish (Spain): La corporación en la que trabajamos todavía es pequeña. - The corporation in which we work is still small.

The relative pronoun quien is strictly for people. Because la corporación is a thing, we use the definite article plus que after the preposition instead. Since the word is feminine and singular, it becomes la que.

Is it possible to just say en que without the la?

Yes! With simple prepositions like en, de, and con referring to things, you can often drop the article. Saying la corporación en que trabajamos is perfectly correct, though en la que is very natural and common in everyday speech.

Since the corporation is going to grow, shouldn't we use está pequeña instead of es pequeña?

That is a common mix-up! Even if a characteristic might change over time, size is treated as a fundamental, defining trait of the subject in Spanish. We always use ser (here, es) for physical traits like size, color, and shape.

Could we place todavía somewhere else in the sentence?

Yes, adverbs like todavía are quite flexible in Spanish. You could say es todavía pequeña or es pequeña todavía. Placing it right before the verb is just a common way to naturally emphasize it.