Can anyone tell me the day to day activity of windows server administrator and roles and responsibilities?

Server administrators basic job description varies from the type of company. 

For me i think the basic tasks would be,

Perform daily system monitoring

carryout backups

installing system updates and patches

preventive maintenance

basically making sure the system is unto date and runs smoothly. 

First  I will check IT room Temperature, Check every Server is working Perfect, Check Backup fully completed  or any error, update patches , create/Delete/Edit user Account, create/delete/edit user permissions, audit and notification Network and systems,  its depends on the company you work for. in a large corporate environment you might specialize in one area such as  Database, Windows, Storage , Desktop, etc in a small environment, you may be the only IT Support And will be required maintain everything. Worked on the migration process of Domain Controller Migration from Windows Server 2003 to Windows Server 2008, 2008 R2 and 2008 R2 to 2012 ,2012 R2. Responsible for AD replication and Meta data cleanup task whenever any Domain controller down or any hardware issue

Monitoring the Server System, checking the event logs, and at the same time checking the hardware logs too. Checking back up status. Updating the server OS patches on time, threat monitoring and further updation. Audit the login details; AD replication, Group policy health status etc.

First  I will check IT room Temperature, Check every Server is working Perfect, Check Backup fully completed  or any error, update patches , create/Delete/Edit user Account, create/delete/edit user permissions, audit and notification Network and systems,  its depends on the company you work for. in a large corporate environment you might specialize in one area such as  Database, Windows, Storage , Desktop, etc in a small environment, you may be the only IT Support And will be required maintain everything. 

• Server administrators basic job description varies from the type of company. 
• Package deployments and support thereof
• Patching
• Break/Fix
• Capacity Planning
• Capacity and Performance Advisory
• Looking into disk and storage issues
• Looking into memory and performance issues
• Making recommendations
• Security changes
• Crash investigations
• Tuning

 responsible for Installation , Upgardation and decomission of all windows machines .Troubleshoot Windows Server Performance issues using various performance and monitoring tools. Worked on the migration process of Domain Controller Migration from Windows Server 2003 to Windows Server 2008, 2008 R2 and 2008 R2 to 2012 ,2012 R2.responsible for AD replication and Meta datacleanup task whenever any Domain controller down or any hardware issue . Patch Management and Change Management . Need to initiate Proactive Task like Cluster Mainatainence , Manual Ptaching on Servers ,Need to upgrade ESXi Host patching  

Thank you, could you please elaborate, how you will do backup, and through which backup tools, what are the PM activities you will do?

you must make sure :

1.installing system updates and patches (specially security updates)

2.snapshots and backup (Regular )

3.Full Featured Antivirus (malware,spyware ,randsomware etc..)

4.Perfect Firewall configuration

5.other perfect system configuration (like user account control ,browser settings ,ask before delete etc...)

6.network and system audit and notification setup 

other things depends upon what service it provides like file server,web server,AD,DNS etc ..