In most countries, you need to live there for 5 years before you can apply for citizenship but if you are married to a citizen, the wait is often shorter usually 3 years.

Time spent as a permanent resident or green card holder usually counts toward the requirement so you must live in the country continuously, without long trips abroad.

Some countries allow you to apply after 2 or 3 years, especially if you have special ties like ancestry or marriage.

Refugees or asylum seekers may qualify for citizenship sooner, depending on local laws but in this condition, you usually need to be physically present for a certain number of days each year like 30 months out of 5 years.

In some cases, time as a student or worker does not count unless you later get permanent residency but, in this situation, you must also meet other requirements like good moral character and passing a language or civics test.