curl -X POST "https://api.smtp.bz/v1/smtp/send"
-H 'authorization: API-KEY'
-H 'content-type: multipart/form-data'
-F 'from=info@mycompany.com'
-F 'name=Elvis'
-F 'reply-to=elvis@mycompany.com'
-F 'to=postmasterbz@mail.ru'
-F 'subject=My letter subject'
-F 'html=<html><head></head><body><p>My text</p></body></html>'