In my understanding with regular license, my client will be able to advertise & sell without any trademark complications. But that design is not exclusive to them & others can also use the same design.
In case my client wants an exclusive rights (so no one else can use it), should we go for extended license?
There’s no such thing as an exclusive license on envato.
The client can use the end product within the license terms but that does not include claiming copyright - that remains with the author.
First, thanks for the prompt reply.
Is there a possibility of copyright buy-out from the author? Possibly on designs never bought/sold before?
The Extended license is few times higher than Regular, so what’s the use for that?
Apologies if my questions are silly, better silly than sorry 
There no buy out on this marketplace - you would need to contact the author and ask them but that agreement/payment etc will be between you and envato will not be able to protect/be involved
Extended licenses use vary depending on what the item but typically it is about how an item is used.
For example with a website theme - an exclusive license
Would be required if the website was subscription or pay to access based.
Ok. Thanks a ton! Really appreciate the promptness.