DOLFINx, as most finite element software, map the integrals back to the reference element and use a quadrature rule for numerical integration.
In particular, one can choose the quadrature degree (see: How many integration points are included in the tetrahedral grid? - #2 by dokken) or check the estimated degree (which is automatically applied if no degree is supplied), How to obtain the Gauss quadrature degree estimated by the form compiler - #2 by dokken
In DOLFINx, you can supply custom quadrature rules in the following way: Total number of gauss point - #2 by dokken