It depends on how you are modeling the bolts:
- As solids (usually simplified to cylinders): https://www.youtube.com/watch?v=ZSDf1bNXo8g - then you can use *SECTION PRINT to get the forces: Forces in a Bolt
- With simplified model, typically involving 1D elements: https://www.youtube.com/watch?v=pS-OEiUN488 - then it also depends on what kind of 1D elements and MPCs are used, but you can usually obtain the reaction forces directly.
This thread can also be helpful: Best way to find force in bolted connection
As well as many other threads here and on the CalculiX forum if you search for “bolt forces”. This is probably the most common topic here.
Here’s a similar case too: Cantilever Beam - Not Converging on Static Step