Is there a way to put attachments in the body of the message and would
that help?
Some things you can embed, but in general, attachments are attachments no
matter where you might see them positioned in the new message window. Their
position is cosmetic. The problem you're experiencing is, as Gordon said,
that you're sending messages in an encoding that the non-Outlook mail
clients can't handle. If you are choosing Plain Text or HTML and some (but
not all) of your recipients still cannot see the attachments, then you may
still be sending the messages to those recipients in Rich Text, since there
is a per-recipient setting that can override the general Outlook setting if
the recipients are in your Contacts folder.