The best way to translate from English to Spanish depends on the purpose of the translation.
Personal Use: If accuracy is not important and if your purpose is simply personal understanding, then machine translation such as Google Translate or DeepL would be sufficient.
Official or Legal Use: English to Spanish translations for official or legal use typically need to be completed by a certified human translator. The translation then needs to be accompanied by a notarized certification letter from the translation company.
Professional Use: If the translations are required for professional use such as for marketing materials, professional human translators must be employed. If the content is technical, human translators who have expertise in the related field must be used so as to ensure translation accuracy.