How to add your own custom theme
Adding a new theme for your users is very easy. Just copy the extracted or built on your own theme to HOST installation_dir/core/2.3/ip_themes/ folder.
To remove any theme just delete the folder of that theme. Be careful when deleting! Before deletion make sure none of the websites are using it.
With Multisite you get Theme Market at no cost. Which means that your users will be able to select or buy any theme from Theme Market. Once new theme is added it will become available to all your customers instantly.
This option allows you to broaden your theme sales to all ImpressPages users.
In case you want more pre-built themes for your MultiSite, one of ImpressPages community members - Violeta Dimitrova - is ready to help you.
She already has theme packages for multiple purposes: Business, Nature, Family, Beauty, Personal.