Hi @Ibrahim hasan
About the detailed steps to install Exchange Cumulative Update, I would also recommend the Exchange Deployment Assistant.
It would guide you through the upgrade.
And since you should have a DAG deployment, you may also need to first put the Exchange server which you would like to upgrade into maintenance mode.
Here are several links which may be helpful:
Installing updates on DAG members
Performing maintenance on DAG members
About the whole process: Installing Cumulative Updates on Exchange Server 2016
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
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