With Life Insurance there are no initial exclusion periods. Once the policy is in force you are covered and the claim will be paid if you die within the policy term.
However, there can be initial exclusion periods applied on payouts for suicide. Some insurers require you to have the policy in place for 12 months before they will pay out due to a suicide.
It is important to talk with an adviser if you have any questions like these as each insurer can have their own rules regarding certain circumstances and the adviser can make you aware of these fully before purchasing any policy.