I drive a 2012 Ford F-150 3.5L V6 Twin Turbo ECOBOOST, is it possible for an f-150 to engine swap a 3.5L V6 Ecoboost to a 6.7L V8 diesel?

 

Trading trucks would be cheaper and make more sense.

 

Roadie is right, but if you REALLY had your heart set on swapping engines.
Consider that you'll have hours of time in researching what parts you're going to have to change, locating those pieces (engine, trans, axles, fuel tank, etc.), the labor to put them all together (your own or a mechanics). By the time you've finished you might have twice or three times the money it would take to buy a 6.7 diesel outright.
That said anything is possible...

 

And when you got ready to sell it, nobody is going to want to buy a butchered diesel F150.

 

Any thing is POSSIBLE but not everything is PRACTICAL.. What you wanting is definitely not practical.