Learn Polish: Szefowa musi posprawdzać nasze dokumenty. - The boss has to check our documents.

This highlights the distributive prefix po- from your current lesson. While sprawdzić simply means to check something completely, posprawdzać emphasizes checking multiple items, often one by one or as a batch. It perfectly matches the plural object dokumenty, painting a picture of the boss going through a whole stack of them.

I noticed po- is added to sprawdzać (the imperfective verb). Is that how these distributive verbs are usually formed?

Yes! To create a distributive perfective verb meaning to do an action to multiple objects, you typically add the prefix po- directly to the imperfective form of the verb. That is why we use sprawdzać instead of the standard perfective sprawdzić as the base.

Why is nasze dokumenty in the accusative case here?

The case is controlled by the verb that directly acts upon the noun. Even though musi is the conjugated verb in the sentence, the direct object actually belongs to the infinitive posprawdzać (to check). Since checking takes a direct object, nasze dokumenty is in the accusative case. Because it is an inanimate plural noun, its accusative form looks identical to its nominative form.

Is szefowa the standard word for a female boss, or should I just use the masculine szef?