Not freehand. We have dropdown boxes for position (lateral, supine, prone), arm position (tucked, armboard, arm sling for lateral), leg position (lateral, prone, supine, frogged), and positioning aides (axillary roll, head support, knee support, etc.). We also have defaults that these can be pre filled for us, just need to check that everything is correct. Part of our timeout includes checking the position with the surgeon and is documented as such.
For a minute, I thought you were asking how to document "free arm" positioning, as in draping for an axillary node dissection.
You should always document that positioning was approved by both the anesthesia team and the surgical team. If you don't have a drop down box that states both of these, you should write it in your nursing notes.