Question

How can I get my all contacts when I change my phone or sim?

Answer 1

What kind of phone do you have? I use an iPhone and I store my contacts on the cloud. When I get a new phone, they are automatically downloaded once I sign into my account.

Answer 2

If you have google account then go to google contacts and you can update all the contacts from there. or you can import it from contacts settings. Go to contact menu of your phone > Settings > Import/Export contacts its that simple