At the moment, all the applications that require a domain name during the purchase can only be used with a domain name registered with Namecheap and pointed to the Namecheap BasicDNS or PremiumDNS servers.
This is a temporary limitation, but right now, there is no fixed date when this prerequisite will not be necessary.
At the moment, there are four applications that do not require a domain name at all:
Also, the EasyWP application does not require a domain name upon purchase and you can either use an .easywp.com based free domain or add a custom domain name later. Domains registered with a third-party registrar can be used with EasyWP using an URL Redirect option. You can find more information regarding this option here.
If you have any questions, feel free to contact our Support Team.