Question

what is the role of post office in modern era

Answer 1

Although with the modernization the role of post offices seems to be decreased as the people use modern ways and technology instead of it. But still there are the roles that post office play in modern era.
The transport of your necessary document from one city to another is easily and safely done by the post office.
The letters from government documents from job's organization are delivered to one's house using the post office. 
Moreover , the some of minor luggage can also be delivered by the posting .
These post offices still have role to transferred the material from one place to far away places.

Answer 2

Today, post offices help in much more than sending letters and parcels to people staying away from you. You can avail post office services to send money to people staying in other states or even in the same state. You can open MIS accounts by making a deposit and getting monthly returns for the same at a specified interest rate to manage your expenses. The PPF is one of the best services offered by a post office. You can make a small deposit every month for a maximum period of 15 months and a tax-free interest. The post office also offers various other types of accounts and a special saving scheme account for senior citizens.