The Apps that show up in Canvas come from the Edu App Center and you can submit App there and then either have the just available to your local Canvas instance, or publicly (subject to approval by Instructure).
There's more details on how you manage the Apps that appear in Canvas on: https://community.canvaslms.com/t5/Admin-Guide/How-do-I-manage-an-Edu-App-Center-allow-list-in-Canva...
However at the moment the Edu App Center only supports LTI 1.1 tools (old standard) so if you've developed a LTI 1.3 tool (recommended these days), there doesn't seem to be a simple way to get it appearing in Edu App Center.
