Change URL to access owncloud

Hi,
I have an ownCloud server and it works perfectly. I'm using a https://domain.com/owncloud or https://www.domain.com/owncloud and it would like to know : is it possible to use something like https://cloud.domain.com ?
I use Letsencrypt for my domain.com / www.domain.com, is it necessary to create a new certificate for cloud.domain.com ?
Thank you !

Yes, the documentation contains the info how to do that:

https://doc.owncloud.org/server/9.1/admin_manual/installation/changing_the_web_route.html

Yes

Hi,
Thank you.
I'm sorry but I'm a newbie on Ubuntu and ownCloud, do you have an example to use cloud.domain.com instead of domain.com ?

Did you follow the instructions in the linked document, it already shows the steps. In your case, you may want to change
ServerName domain.com
into
ServerName cloud.domain.com instead of
in your SSL-Vhost.

Yes I read instructions but I don't understand how can I use cloud.domain.com. It's the first time I use Ubuntu, Apache and other.
Is it necessary to change Alias / "/var/www/owncloud/" ?
And do I use 'overwrite.cli.url' => 'https://cloud.domain.com', for this ?
I don't want to use root access so this step seems to be useless :...
#### DO NOT CHANGE ANYTHING ABOVE THIS LINE ####
...

RewriteBase /
...

Can I set my personal domain name like cloud.mydomain.name using ownload.online ?