Mail-merge
The production of similar documents where individual items are inserted from the fields of a database...

.... is called mail-merge.

A standard form letter is created using a word processor....

Dear <Name>,

Please attend an appointment at <Time> on the <Date>

Yours etc.
The Doctor

...and a database with the fields <Name>, <Time> and <Date>...
Name Time Date
Tom Evans 9.30am 3rd May
Will Smith 3.45pm 4th May
Mary Jones 2.30pm 2nd May
When the merge is performed the result is a letter for each record in the database. The data from each record is inserted...
Dear Tom Evans,

Please attend an appointment at 9.30am on the 3rd May

Yours etc.
The Doctor

 
Dear Will Smith,

Please attend an appointment at 3.45pm on the 4th May

Yours etc.
The Doctor

 
Dear Mary Jones,

Please attend an appointment at 2.30pm on the 2nd May

Yours etc.
The Doctor