Mac mail Attachments can no longer be embedded in the body of the email. They are defaulting to the bottom of the email after the signature. Even worse they go to the bottom of a thread.

Interesting - just did a Dummy Test as a Reply to the e-mail received from Apple Support Communities with your posting

Use the Attach file and placed a file in Top Left of the Body of the e-mail and Dragged it into the position appearing in below image/

It did move

westcountychick wrote:

That's how it used to work. For years. But suddenly not. I can not paperclip. I can not drag and drop I cannot copy and paste . Any attempt to do so results in the attachment placing itself at the bottom of the email, after the signature line or the last character in the text. If threaded, the bottom of the thread. I have tried not using signatures. I have tried every manner of attachment in every manner of attaching.

Q - " Any attempt to do so results in the attachment placing itself at the bottom of the email, "

A - Once the Attachment is placed in the Body of the e-mail, juts Drag the Attachment to a new location in the Body of the e-mail

A - I use a Signature sometimes. Yes, the Attachment might be Below the Signature but Draging It to a new location always has worked in Big Sur and Monterey for me.

A - An Aside, regardless to where the attachment is located and depending on the Recipients e-mail Client - the Attachment may appear to them as a File Attchment and outside the Body of the e-mail. That is beyond the Control of the Sender ( you )

westcountychick wrote:

At this point I am going to rebuild all my mailboxes and see if that fixes it since clearly others are not affected.

Please don't do that. It "rebuilds" by deleting everything and downloading it again from the server.

In Apple Mail, go to the "Edit" menu. Look for "Attachments". Is "Always insert attachments at end of message" checked?

Select the paper clip icon or image icon, you can upload the doucments and embeddded in the body of mail.

Good work and consider marking your above as " Solved " designation ( Closed ) for Others with similar issue can easily find the solution.