How to email a Score

When I go to my e-mail and compose a new email, ( to send my score Via- Email )
then select attachments,
then Documents,
then Musescore3,
then Scores,
then choose the light blue mn with the MSCZ file
and send,
So after I recieve it in my E-Mail I open the email up,
I download the attachment and then,
It gives me a window that says: Load Error cannot read!
It won't open the attachment.

1- Do I have to convert the MSCZ file to a PDF? ( How do I do that )
2- How do I share my Score ?
Thanks
-Jan