( Peace up on you )
السلام عليك asalam alika
It should say for one person
السلام عليكم asalam alikoum
For group of people
But if you said السلام عليكم for one person it give more respect and more formal
( Thank to you )
شكرا لك shukran lak
It should say for one person
شكرا لكم shukran lakom
It should say for group
But if you say shukran lakom for one person it will give more respect and more formal