My favourite WP plugin for backing my WordPress site up and also for moving it is:
All in One WP Migration Plugin
All you need to do is load the plugin. Then click on export and the plugin will guide you to export it in any way you choose. I usually choose file – meaning to my computer. I do backups like these after every update of my WP site or new posts or alternations.
To migrate or restore the site, all you need to do is create a new WP installation. Then load the All in One WP migration plugin and then import the backup file from your computer or source where you stored it. Just remember at the end of the restore process to save the Permalinks twice. That seems to be a very important step.
Another good plugin is Duplicator. Although it’s a bit more finicky with the specs required from the server to make it work.
So what is your favourite plugin for migrating your WordPress sites?