What is the best format of a logo file to imprint on promotional pens?

What is the best format of a logo file to imprint on promotional pens, mousemats or other this type of items. I need to create one and tbh have no idea which software to use.
Do you know if companies who sell this kind of products do this for me??
Thanks

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).