Want to add a picture, video, PDF, Pages document or other file to an email in Mail on the iPhone? Don't worry: it's easy.
(We'll be attaching the file to the email itself, which is suitable for small or medium-sized files only. If you want to send something really big, you'll need the advice offered in our article How to send large documents & files from an iPad or iPhone.)
Open Mail and open or create your email message. If it's an entirely new message, you should tap the 'pen in a square' icon at the bottom right of the screen; but more commonly you'll be opening an email from somebody else and tapping the reply icon (an arrow curving to the left) and then Reply again.
You can attach the file at any point in the composition of the email; once it's been added you can carry on typing, or just send it as is.
When you're reading to attach a file, do a long-tap in the body copy of your email (a normal tap that just lasts a bit longer, not a harder press to activate 3D Touch). A double-tap will also work. Either way you should see a black ribbon menu starting with 'Select'.
Tap the right-facing arrow on the end of the ribbon to see more options. (You can tap the righthand arrow yet again to see even more as appropriate, but we'll be working with the second page of options.)
If you're emailing a photo or video that's stored in the Photos app, select the first option now visible: Insert Photo or Video. This will take you into your Photos folders, and you can select a file to attach from there. Open the correct file, then tap Choose at the bottom right, and it will appear in the body of your email.
If you'd like to attach a different sort of file, or a photo that's stored elsewhere, select the more generic command Add Attachment. From here you can choose from recent files, or browse ones that are stored in iCloud, in your apps (such as Pages) or in a range of third-party services such as DropBox.
How to remove an attachment from your email
Once you've attached it, the file largely behaves like any other element of an email. If you put the text cursor to the right of it and then tap backspace, it will be deleted. (If you do this accidentally, remember you can shake your iPhone and then select Undo.)