As you can see in the attached file Sheet 1 contains 3 items in the drop down list
As you select each item the model also changes

I query is that I want to give only 1 print command and in this print command

Item 1 is selected and a print out comes out with the corrosponding model

Then Item is automatically selected and model is also changed automatically and next page print out comes out

Same way for the third item item it is selected, the model changes accordingly and print out comes out

Currently I have to do it manually by selecting each item and giving a new print command for each, which takes a very long time.

Try recording a macro that captures the selections you make. Then save it and just runt he macro.