If you can't send mail, but you can receive, and you're using the Mac Mail app, the cause could be malware. Here's the simple fix.
Everything you need to know about attaching files to Mac Mail messages. Includes eleven ways to do it! The Definitive Guide.
The Mac Mail app shows attachments as icons, unless they're single-page PDFs or images. If you want everything to be icons that's doable.
Here are my top ten tips for using Mail on an iPhone (or an iPad). They make using Mail faster, easier, and more efficient. Give them all a try!
iPhone's Mail app worked on WiFi, but not on cellular. Yet Safari worked fine whether on cellular or WiFi. Hmmm. Here's how I fixed things.
Here's a video showing how you can customize the Mail app's toolbar on your Mac, making it easier and faster to use.
When addressing an email, do incorrect email addresses pop up? Would you llke to clean that up? Of course you would. Here's how.
Here's how you change the size of the text of incoming Mail messages, and the size of the text in the message list.