Drilling into granite columns. How to do it correctly?

Hello,

We are currently planning a privacy fence along our property boundary.
As posts, we want to have 15x15 cm granite posts installed by a landscaper.
We want to do the installation of the privacy fence panels ourselves.
I am a bit confused. On the internet, you find contradictory information on how to drill into granite. Of course, you need a suitable drill for that, that is clear. But on the one hand, you read that you need a hammer drill with sufficient impact to drill into granite. On the other hand, you read again that you should definitely not drill with impact. So what now?
Does anyone here have any advice?

Best regards
Chris

Without a rotary hammer, this is a very strenuous undertaking. At 15*15, I also see little problem. I would drill the holes before inserting the columns.

I only drilled my granite with the rotary hammer, had no problems.

Bosch GBH 18V-26F + the 7x drills from Bosch