Typically, a lien holder will require you have the state minimum liability coverage on your vehicle, plus list them as an "additional insured." The insurance company should then list your lien holder on your insurance policy if you provide this information and they will send a declarations page to the lien holder normally.
Any lien holder, additional interest, or loss payee will receive notification of insurance. A copy of the declaration and/or any policy status forms are mailed to them. In addition, each insurance companies' service department can provide a faxed or replacement copy of any proof, if the lien holder needs additional proof. You should not need to request any documents to be sent to the lien holder, it is an automatic process.