Usually fairly quickly provided the Beneficiary has the Death Certificate for the deceased.
Sometimes a company will accept an obituary or some other proof of death, but usually they want the actual certificate.
After they receive it, most companies will send you a check within 2-4 weeks max.
If there are suspicious circumstances around the death it could hold up the process.
To add to what Tyler said, the first concern many people have is how to pay for funeral expenses. Most funeral providers will accept a "collateral assignment" against the life insurance proceeds. This is a lien filed immediately with the insurance company that provides that the funeral provider be paid first directly from the insurance company with the balance of proceeds going to the beneficiary.
Sometimes a company will accept an obituary or some other proof of death, but usually they want the actual certificate.
After they receive it, most companies will send you a check within 2-4 weeks max.
If there are suspicious circumstances around the death it could hold up the process.