there is many people and no body is able to answer me correct one. here is the answer i found and that 100% works for all the Ubuntu versions
Enable snapd
If you’re running Ubuntu 16.04 LTS (Xenial Xerus) or later, including Ubuntu 18.04 LTS (Bionic Beaver) and Ubuntu 20.04 LTS (Focal Fossa), you don’t need to do anything. Snap is already installed and ready to go.
Install tvheadend
To install tvheadend, simply use the following command:
sudo snap install tvheadend
by the way i think no benefit so far for asking any thing here