There are different ways to link documents in mail instead of inserting the documents as attachments.
Recent documents used in OWA
By clicking on the attach file icon in Outlook Web App, you get a menu that shows Suggested files. These are the last files you have opened in Onedrive or Sharepoint. By selecting one of these files, a link is automatically generated and attached to the email you are about to send.
Link to document in Teams (Sharepoint)
Navigate to the document that you want to share in Microsoft Teams as part of a mail. From the context menu, select Copy Link.
Choose to copy the link you get by clicking the Copy button. Close the window and go to the mail you are writing in Outlook Web App.
Paste the link into the mail you want to send.
Link to document in Onedrive
Navigate to the document in OneDrive that you want to share. Right-click on it and from the context menu choose Copy Link.
Paste the link into the email you want to send.
Link to document in Vortex
Navigate in the browser to the folder in Vortex where the relevant document is located.
Click on the About tab and copy the URL of the document.
Note that access to this document is controlled by what is set under the Rights tab. If the person you are sending an e-mail to does not have the necessary access, they will not be able to download the document and open it. This prevents a document containing sensitive/confidential information from falling into unauthorized hands (e.g. by sending the e-mail to the wrong person).