Does it vary depending on the life insurance company or is there a general effective date?
If your life insurance policy starts today, it's effective if you die tomorrow.
But you can't put life insurance in force quite that quickly, most of the time.
Keep in mind, no life insurance will cover suicide that happens in first two years, but I think its one year in the State of Colorado.
There is such a thing as "conditional acceptance", where it becomes effective right away, as long as all of your answers check out, on the life insurance application. If you lie about something, though, and they can back out.
Here's how you can learn about instant term life insurance and find out how you may apply for coverage online today.