The presence of suffix -kan can be used to make transitive verbs and benefactive verbs.

For one large group, ‘-kan’ is simply needed for the verb to be formed correctly. Although the ‘-kan’ has no obvious meaning it must be there. Examples:

Some of this group have a matching intransitive verb without “-kan”. Example:

Kami memikirkan[berpikir tentang] hal itu.
We thought about the matter.

In such pairs, the transitive “-kan” verb has an advantange over its intransitive ‘twin’; namely, it allows you to focus on either the Actor or the Undergoer. So (e.g.) you can say either:

Kami memikirkan hal itu. – [= focus on the Actor: “Kami”] OR
Hal itu kami pikirkan. – [= focus on the Undergoer: “Hal itu”]

But if you use the intransitive verb, like ‘berpikir’ you cannot focus on the Undergoer. There is no Undergoer. So you could not begin with “Hal itu…”. Instead, you must focus on the Actor, and say “KAMI berpikir tentang hal itu.”

‘-kan’ can also be added to some verbs that are already transitive. In these cases, -kan shows that the action is done for someone. There are two ways to say it:

OR

When it is obvious whom the action is done for, that person is often not mentioned. Examples:

————–
Note:
Very often when speaking, Indonesians use both ‘-kan’ and ‘untuk’ to show that the action is done for someone else (e.g. “Edy membelikan koran untuk ibunya.”. But not all educated speakers regard this as correct.

Reference: Dr. Timothy Hassall, Indonesian Grammar, ANU – Canberra.