Most people open emails on their phones, so emails must be easy to read on small screens. Use short subject lines so they do not get cut off on mobile inboxes. Write short paragraphs and leave space between lines to make reading comfortable. Buttons and links should be big enough to tap without zooming. Avoid heavy images because they load slowly on mobile data. Test your email on a phone before sending to see how it looks. Simple design and clear message work better than crowded layouts. What do you think?