Every form of Indonesian verb starts with a 'root'. It then often gets loaded with prefixes (which get attached to the front of the root word) and suffixes (which get attached to the end of the root word). The prefixes and suffixes (together called 'affixes') can change the verb's meaning or purpose.

Take the verb "mandi", to wash. Remember that "aku mandi" means "I wash". "Aku mandikan anjing" means "I wash the dog".

So, "-kan" can make the verb transitive or is used when you are doing something to something.

More examples:
"Aku masuk ruang" (I enter the room) becomes "Aku masukkan kertas (dalam laci)" (I insert the paper in the drawer). `

"Kan" can also do other things. It can mean that you are doing something for someone else.

Example: "aku buat kopi" (I make coffee) becomes "aku buatkan kamu kopi" or "aku buatkan kopi untuk kamu" (I make you coffee).