new domain instead of old domain

if a change domain for a well google-indexed site, how to do to avoid impact?

let old domain redirect to new? how?

as soon as possible let google delete old index and index new site?

does google think new site as a duplicated site?

 

if you use 301 redirect and close the old site, G will not consider that you are dublicating content. make a google search about 301 redirect

 

use permanent redirect from your old domain to new domain...it will take some time for google to refresh their index.

 

what is permanent redirect ? r there temp redirect?

 

301 redirect in an apache server .htaccess:

Redirect 301 www.oldsite.com www.newsite.com

HTML:

Its best if your new domain name reflects your business.