If you're okay with bootleg torrents, nyaa.si has it. It's a public tracker but I've never gotten an angry ISP letter from using them.
If you mean legally, you might have to buy DVDs. Just make sure you get ones that are the right region, especially if you buy them off Amazon.
Install Kodi: https://kodi.tv/download
Install Covenant Add-On for Kodi: https://seo-michael.co.uk/how-to-install-the-covenant-kodi-krypton/
Use Covenant to search for Dragon Ball.
Watch any Dragon Ball/Dragon Ball Z/DB Super/etc.. ever made
(This works best if you install Kodi on a Raspberry Pi but it can work on anything)