Activate your file 1) by tapping the blue icon before the title of the document. 2) Then choose Share (can be found in many spots, as in the image below). 

Always check the permissions you are sharing the link with. By default OneDrive is sharing files with editing permissions. With video files this means that the link user is able to download the video onto their computer. This is often useful, since the users without Diak credentials might have difficulties in viewing the video in browser (for which viewing permissions are sufficient). However, with text documents you should always consider when to share editing permissions. Most assignment submissions in Diak moodle are meant for internal use and viewing only unless otherwise agreed with the teacher. Editing permissions are needed if feedback is given directly into the OneDrive assignment or for example if a group submission is to be reedited after submission. 

You may change the permissions by clicking on the green ball icon. If you do not wish to make any changes to the default link sharing permissions, click Copy Link/Hae linkki. 

Copy the link by clicking on the Copy/kopioi-button. You may also copy the link with Ctrl + C and paste it with Ctrl + V. After copying the link onto the clipboard, you may close the pop-up window.

Open the assignment, click on Add submission and paste the link into the text editor box. Remember to Save changes. 

If the text box is not activated by the teacher, you may insert the link into a Word document and then submit the file for the assignment.