Эта форма показывает, что кто‑то был обязан что‑то сделать в прошлом.

This form shows that someone had to do something in the past.

Breakdown of Эта форма показывает, что кто‑то был обязан что‑то сделать в прошлом.

• в: in
• быть: to be
• что-то: something
• что: that

Questions & Answers about Эта форма показывает, что кто‑то был обязан что‑то сделать в прошлом.

Why is показывает in the present tense if the sentence talks about something in the past?

The verb показывает is in the present tense because it refers to what the form does now or in general, not to when the obligation existed.

• Эта форма показывает… = This form shows… (a general, timeless statement about meaning)
• Inside the что‑то был обязан сделать clause, we switch to the past (был) because that clause describes an obligation that existed in the past.

So you have:

• outer verb: present (what the form does as a grammatical form),
• inner situation: past (what someone was obliged to do).

This is very similar to English: “This form shows that someone was obliged to do something in the past.”

What does эта форма mean here? Is it a physical form (like a document) or a grammatical form?

By itself, форма can mean:

1. shape, form (physical shape),
2. form, application form (a document),
3. form in the grammatical sense (verb form, case form, etc.).

In grammar explanations, эта форма almost always means “this grammatical form” (for example: this tense, this verb ending, this construction). So here it is not about paperwork but about a specific grammatical form in Russian that carries the meaning “someone was obliged to do something in the past.”