I'm currently working in TechM and I want a LOR from my reporting manager but the company doesn't provide letter head.

I'm currently working in TechM and I want a LOR from my reporting manager but the company doesn't provide letter head. It's the same with my previous employers as well. They are just providing detailed experience letter. Is it enough for applying MSCS in USA? Or recommendation through email is enough from my reporting manager or colleague through official email id ?