You can do
mv car.txt bicycle.txt vehicle/
(Note that the / above is unnecessary, I include it merely to ensure that vehicle is a directory.)
You can test this as follows:
cd #Move to home directory
mkdir temp #Make a temporary directory
touch a b c d #Make test (empty) files ('touch' also updates the modification date of an existing file to the current time)
ls #Verify everything is there
mv a b c d temp/ #Move files into temp
ls #See? They are gone.
ls temp/ #Oh, there they are!
rm -rf temp/ #DESTROY (Be very, very careful with this command)