When I add an Account to a Contact on the Edit Details page, the Mailing Address field is auto populated with the address from the Account
|Knowledge Article Number||000187004|
|Description||When adding an Account to a Contact on the Edit Details page, if there is an address for the Account, this will auto-populate for that Contact.|
This is a standard feature of Salesforce and working as designed.
NOTE: IF Account Billing Address is populated, Mailing Address will be auto-populated in Contacts upon creation.IF Account Billing Address is BLANK and (Shipping Address is POPULATED OR BLANK), it will not pull the value on Contact Mailing Address upon creation.
So in effect it only pulls the value from the Billing Address on Account.
Regarding other fields that gets populated refer to this article - What account information will autopopulate a contact record?