Attaching docs to emails

To attach a document, place the cursor at the insertion point - then tap the screen; you will see a set of actions appear.

If necessary, tap the ">" button to expose more options, then select Attach File - then navigate to and select the document that you wish to attach to your email.

You're very welcome.

An alternative method is to use a split-screen or slide over window - having both your draft email and Files App windows visible. Simply drag-and-drop the file/document from the Files window to the draft email.