assuming that you are using a poor hosting service without automated daily backups ... and a secure one without exec and passthru usable with your php
you have 3 parts :
- the entire database,
- optionnaly , the uploaded images directory if you set it
- the software
The database and the directory must be saved each day. The software , each time after any update , but it is ready on github. A good practice is to have the web content master on your own disk
To save manually the database, use phpmyadmin . If passthru or exec are available in your php, try to redirect mysqldump to a file. Or, try to install
https://github.com/ifsnop/mysqldump-php .