Attaching a file

Moved to Attach a File to a Page.

Using the attachment tab at the bottom of the page

Moved to Attach a File to a Page.

Using the WYSIWYG editor

Moved to Attachments Tab in Page Extra Area, which covers attaching a file from the editor.

Using the top level menu

Moved to Attach a File to a Page.

Moving an attachment

Moved to Move or Rename an Attachment.

Deleting an attachment

Moved to Delete an Attachment.

Linking to an attached file/image

Moved to Link to an Attached File or Image.

Linking to an external file/image

Moved to Link to an Attached File or Image, which also covers a file that is not in the wiki.

Backlinks indexation

Moved to Attachments Tab in Page Extra Area, which explains how attachment links are indexed.

Upload summary

Moved to Attach a File to a Page. Whether the summary field is offered at all is an administrator setting, covered by Enable Attachment Upload Summaries.

Size Limit

Moved to Attachments Tab in Page Extra Area, which covers the size limit and the mimetype restriction as a reader meets them. Raising the limit is an administrator task, covered by Set the Maximum Attachment Size.

Learn More

Moved to Attachments Tab in Page Extra Area.