There are lots of different types of websites, and whether you're using Squarespace, Wordpress, Wix, Weebly, or something else, most of them have a way to upload a video file or add a YouTube video to your pages.
First, follow our guide to downloading your video on either desktop or mobile. Then check out one one of these guides below to add your video to your website.
Squarespace — Adding your video to Squarespace
Wordpress — Including video in Wordpress
Weebly — Embed videos in Weebly
Godaddy — Add video to your Godaddy site
Shopify — Adding video with the rich text editor.
Magisto — Embed videos in Magisto.
If you have a custom website not on one of those services or worked with someone else to build your site, you may need to consult with your site contact or reach out to your provider.