Hello, may I ask about leter… I need it to open bank account

Who or what is leter?

I need proof of address, for a bank account

If you contact Bulb direct they will send out a printed copy of a Statement as a one off.
It will be exactly the same as you could print off yourself just a different printer but for some reason the banks cause an issue with it, how they tell the difference I do not know.

Where can I find that for printing

Sign in your account then statements and payments.
Scroll down and you will see your monthly statements.