when I uploaded my purchased theme , and check preview , there are too much unwanted html codes everywhere on my site ?
Have you set it up fully? installed plugins?
yes whatever its recommended
Can you share a screenshot here of what you see?
Certain that most likely the visual composer plugin is not active, or you are using old versions of the theme and/or WP
and also how to apply changes on colors and bachground or whatever ?!!
I used severl time puplished and … but nothing is changed!!
While I am almost certain that the plugin is not activated properly - your best option is to speak to the author https://help.market.envato.com/hc/en-us/articles/203039054-How-to-contact-an-author
ok , thank you