Email template that works for gmail and outlook (mobile and desktop)

My client has a Shopify account that sends emails to their costumers but the emails doesn't display properly in some email apps like windows mail. I need some one to make changes to the existing templates so the style is not ignored by gmail, outlook and windows mail app. There are 31 templates to fix. All the templates are very similar so if you fix one of them you'll just need to copy paste some parts to the other templates.