Backup and Restore SiteCollections using PowerShell

Backup the SiteCollection:

1.Open SharePoint Management Shell from SharePoint Products
2.Create a folder named as "SharePointBackups" in D: drive.
3.Run the below command
   Backup-SPSite -Identity https://sharepoint.com -Path D:\SharePointBackups\mysite.bak -Force
 
   It will create a mysite.bak file in SharePointbackups folder.

Restore the SiteCollection:

Run the below command:
   Restore-SPSite -Identity "Target Site Url" -Path "D:\SharePointBackups\mysite.bak" -Force

It will restore the site collection in target site.