Open your Google Docs document
Place the cursor where you want the video link or preview to appear
Click Insert
Select Drawing
Click New
Add an image or text for the video link if needed
Click Save and Close
Insert the video URL as a hyperlink in the document if desired
Use Google Slides or Google Sites if you need an embedded video preview instead of a link
If the video is in Google Drive, insert a clickable link to the Drive file
If the video is on YouTube, paste the YouTube link into the document and format it as a hyperlink