What do I need to Copy and Transfer?

Hi guys.
I'm Copying Appwrite from One Server to another.
Is Copying MariaDb data enough or You need to Copy Other Things too ?

Copy also all the docker volumes

You can this article as a guideline
https://dev.to/appwrite/appwrite-in-production-backups-and-restores-4beg

Can I change the MariaDb user And Password After its been installed. Because I have some data that needs to be there & need to change the default password?

Sure you can
You do so by update those details inside the .env which located in the same folder as docker-compose.yml

To be exact those are the values

_APP_DB_HOST=mariadb
_APP_DB_PORT=3306
_APP_DB_SCHEMA=appwrite
_APP_DB_USER=user
_APP_DB_PASS=password
_APP_DB_ROOT_PASS=rootsecretpassword

I can change these Values after Initialising them with default password?

Yes
You can set them to whatever you want

And need to Restart the Container?

Yes

Just run docker-compose up -d

It will update only containers the affect by the .env file change

Hello @ORIZON , I think this conversation will be useful:
https://discord.com/channels/564160730845151244/1082652391867944980