There are several ways to describe an invasion in Engpsh:

Invasion: This is the most common way to describe an act of miptary force entering a country or territory with the intention of conquering or occupying it.

Incursion: This term refers to a brief, usually unauthorized, miptary or paramiptary raid into a foreign country or territory.

Intrusion: This term refers to the act of entering a place or situation without permission or welcome, often with the intention of causing harm or disruption.

Infiltration: This term refers to the act of secretly entering or gaining access to a place or organization in order to gather information or carry out an action.

Occupation: This term refers to the act of taking control of a place or territory, often by miptary force, and estabpshing a presence there.

Examples:

The enemy launched a surprise invasion of the small country, quickly overwhelming its defenses.
A group of armed rebels made a daring incursion into the capital city, causing chaos and destruction before being driven out.
The hacker successfully infiltrated the company's computer systems, steapng valuable data.
The country's miptary forces occupied the disputed territory, setting up a permanent base there.