The following information is about Microsoft Stream (Classic) which will eventually be retired and replaced by Stream (on SharePoint). To start using the newer video solution today, just upload your videos to SharePoint, Teams, Yammer, or OneDrive. Videos stored in Microsoft 365 the way you'd store any other file is the basis for Microsoft Stream (on SharePoint). Learn more...
Add videos to Microsoft Stream (Classic) channels and groups
Add video into groups and channels
Click the More icon , and then click Add to group/channel.
Find groups or channels you want to add with the Shared with search box.
Click the group or channel, and then select Add.
Who can add videos to groups/channels
If a video is a companywide video you can add it to any of your groups/channels even if you aren't an owner of the video.
If you are the owner of a video you can add your video to any groups/channels you can contribute to.
Other ways to add
You can also add videos to group/channels as part of uploading a video or editing video details: