I maxed my traditional 401k last year and I've been contributing post tax dollars for the last few months. Now I need to do the in service withdrawal but I'm not sure what options to choose. The 401k is with merrill if that makes any difference.

To get started, I went into my account looking for an in service withdrawal option, but I'm not seeing that. What I do see is a 'start a withdrawal/rollover' option, and a 'in plan roth conversion' option, which, each option has a component in the name of what I'm looking for so now idk what to do.

The in plan roth conversion sounds like it's going to move those post tax dollars into the roth 401k with merrill. I also tried clicking through the withdrawal/rollover section and this apparently allows me to send money to an IRA (though, 'roth' was not explicitly mentioned).

So I guess the question is which one of these is the one I should be doing? Is there any difference between these options from a tax perspective? They seem identical to my untrained eye, aside from the obvious of where the money will be stored following this action and how many investment options I'll have.