If you have a dashboard or a report on one account that you want to copy to another one of your accounts, you have the possibility to do so in your settings:
IMPORTANT: This tool is dedicated to copying the reports and dashboard only in-between the accounts, and is not designed to copy the reports within the same account.
To do the latter, please use this procedure here - essentially the "Duplicate rows from another report" option when creating a new report.
And this procedure for the dashboards.