I want to get my old friend’s mobile no. How can I get it? Only I know his name and address which is very old.
There are services such as whitepages.com, bigyellow.com, etc. that allow you to look up a (published) phone number by name and address. The person's mobile number will only be available if it has been published; usually only home phone numbers (landlines) are published in phone books, however.
Find him on a social network or your local phone directory listing.
You can use true caller app to find some old friends mobile number using his name..