Problem opening attachments
If I send an e-mail with an attachment both created on my Mac under Sierra to my wife's tablet running IOS 11 she cannot open it. What am I doing wrong? She can open Microsoft word attachments. Other people with iPads have also had the same problem so I do not believe it is anything to do with the settings on my wife's machine.
iMac (21.5-inch Mid 2011), macOS Sierra (10.12.5)