During the first two years the insurance company doesn’t have to payout a claim on your death if the death is due to suicide or due to a material fact that was misrepresented on your application for life insurance.
If you are completely honest on the life insurance application and don’t commit suicide, the policy is fully "In Force" from the date the first premium is paid until you quit paying premiums.
However, graded benefit life insurance policies which offer guaranteed acceptance may have limited death benefits the first two years you are insured. After two years, there is usually 100% coverage provided by the policy.