It is possible to run several sites in a single WordPress installation. This is called WordPress multisite (or network installation). It is meant for large environments that have several related sites. At Seravo, WordPress multisite requires at least the WP Corporate plan. Here are the instructions on how you can move a single site inside a multisite if you have such a plan set up.
The Starting Point
A working WordPress multisite installation
A working normal WordPress site
The Process
On the single site, install All-in-One WP Migration and Backup plugin.
wp plugin install all-in-one-wp-migration --activate
On the multisite, also install All-in-One WP Migration and Backup plugin and its Multisite Extension.
wp plugin install all-in-one-wp-migration --activate
Login to WP admin on the single site and export it by using All-in-One WP Migration and Backup plugin (Export > File)
Login to WP admin on the multisite and go to My Sites > Network Admin > All-in-One WP Migration. Import the single site (Import > File > choose the .wpress file exported earlier).
If the multisite is a subdomain type or you want to specify own domains for the subsites, check the domain mapping for the new site: WP Admin > Network Admin > Sites.
Check that the domain for the new site has been added to multisite's routing and that the domains DNS points to a correct server.
Please note that you can always order site transfers from Seravo, by contacting us on [email protected]