Credits towards membership?

Can I use the credits I have to buy the envato membership where they have multiple themes and plugins, also I have a concrete cleanser and roof cleaning services website, but can I use the membership on more than one website?

No you can’t use credits https://help.elements.envato.com/hc/en-us/articles/360000621543-Accepted-Payment-Methods

You can download new versions/licenses for different projects