You can set the html email body for the invitation emails to introduce them to your workspace. You can use the placeholder [Link] if you want to specify the link location. If no [Link] Tag is found in your body, the tag will be appended at the end.
Attachments like the workspace custom logo can be added by using its content id: 'cid:CustomLogo.png'
<img src="cid:CustomLogo.png" />
<h1>Welcome to our Workspace</h1>
Please click this [Link] to choose your password.