Here is why the actor who consistently voiced Megatron in Michael Bay's first three Transformers movies was suddenly recast in the fourth installment.

Source: https://screenrant.com/transformers-movies-megatron-recast-reason-why/

Optimus Prime has a wide range of powers and abilities beyond what is shown in the Transformers movies, including field reconnaissance gadgets and unique alt-modes.

Source: https://screenrant.com/transformers-optimus-prime-powers-abilities-missing/

The Transformers movies always take place on Earth, and here is when the Transformers arrived on the planet for the first time in the franchise canon.

Source: https://screenrant.com/when-transformers-arrived-on-earth-movie-canon/