English is generally simple:
1. Good day or how are you?
2. Self-introduction, company introduction, product introduction and simple summary. I usually write: this is xx of xx company, specializing in the production of xxxxxxxx, with high quality and competitive price.
3. If there is an attachment, say attachment XX for reference.
If there is no attachment, please visit our website for more information.
4. Any questions and inquiries are welcome.
Anyway, what you do can be understood at a glance, and the length should not be too long. I have a colleague who works in the Japanese market and will call after sending an email. The Japanese are very polite and will talk to you for a long time.